Description of problem:
If a RHV provider was already added, with host name FQDN,
Adding this same provider again, will have full refresh fail, 
but failure is not reflected in CFME UI. only in evm.log:

evm.log show that full refresh fail because of using same hostname (I replaced RHV ip address with '<RHV ip address>'):

[----] E, [2017-03-26T07:53:41.326319 #15256:110312c] ERROR -- : MIQ(ManageIQ::Providers::Redhat::InfraManager::Refresher#refresh) EMS: [RHEV-M (<RHV ip address>)], id: [3] Refresh failed
[----] I, [2017-03-26T07:53:41.326389 #3019:110312c]  INFO -- : <AutomationEngine> Followed  Relationship [miqaedb:/System/event_handlers/event_enforce_policy#create]
[----] E, [2017-03-26T07:53:41.326515 #15256:110312c] ERROR -- : [ActiveRecord::RecordInvalid]: Validation failed: Host Name has already been taken  Method:[rescue in block in refresh]
[----] E, [2017-03-26T07:53:41.326607 #15256:110312c] ERROR -- : /opt/rh/cfme-gemset/gems/activerecord-5.0.2/lib/active_record/validations.rb:78:in `raise_validation_error'
/opt/rh/cfme-gemset/gems/activerecord-5.0.2/lib/active_record/validations.rb:50:in `save!'
/opt/rh/cfme-gemset/gems/activerecord-5.0.2/lib/active_record/attribute_methods/dirty.rb:30:in `save!'
/opt/rh/cfme-gemset/gems/activerecord-5.0.2/lib/active_record/transactions.rb:324:in `block in save!'
/opt/rh/cfme-gemset/gems/activerecord-5.0.2/lib/active_record/transactions.rb:395:in `block in with_transaction_returning_status'
/opt/rh/cfme-gemset/gems/activerecord-5.0.2/lib/active_record/connection_adapters/abstract/database_statements.rb:232:in `block in transaction'
/opt/rh/cfme-gemset/gems/activerecord-5.0.2/lib/active_record/connection_adapters/abstract/transaction.rb:189:in `within_new_transaction'
/opt/rh/cfme-gemset/gems/activerecord-5.0.2/lib/active_record/connection_adapters/abstract/database_statements.rb:232:in `transaction'
/opt/rh/cfme-gemset/gems/activerecord-5.0.2/lib/active_record/transactions.rb:211:in `transaction'
/opt/rh/cfme-gemset/gems/activerecord-5.0.2/lib/active_record/transactions.rb:392:in `with_transaction_returning_status'
/opt/rh/cfme-gemset/gems/activerecord-5.0.2/lib/active_record/transactions.rb:324:in `save!'
/opt/rh/cfme-gemset/gems/activerecord-5.0.2/lib/active_record/suppressor.rb:45:in `save!'
/var/www/miq/vmdb/app/models/ems_refresh/save_inventory_infra.rb:74:in `save_ems_infra_inventory'
/var/www/miq/vmdb/app/models/ems_refresh/save_inventory.rb:5:in `save_ems_inventory'
/var/www/miq/vmdb/app/models/ems_refresh/refreshers/ems_refresher_mixin.rb:127:in `save_inventory'
/var/www/miq/vmdb/app/models/ems_refresh/refreshers/ems_refresher_mixin.rb:91:in `block in refresh_targets_for_ems'
/var/www/miq/vmdb/gems/pending/util/extensions/miq-benchmark.rb:11:in `realtime_store'
/var/www/miq/vmdb/gems/pending/util/extensions/miq-benchmark.rb:30:in `realtime_block'
/var/www/miq/vmdb/app/models/ems_refresh/refreshers/ems_refresher_mixin.rb:91:in `refresh_targets_for_ems'
/var/www/miq/vmdb/app/models/ems_refresh/refreshers/ems_refresher_mixin.rb:24:in `block (2 levels) in refresh'
/var/www/miq/vmdb/gems/pending/util/extensions/miq-benchmark.rb:11:in `realtime_store'
/var/www/miq/vmdb/gems/pending/util/extensions/miq-benchmark.rb:30:in `realtime_block'
/var/www/miq/vmdb/app/models/ems_refresh/refreshers/ems_refresher_mixin.rb:24:in `block in refresh'
/var/www/miq/vmdb/app/models/ems_refresh/refreshers/ems_refresher_mixin.rb:14:in `each'
/var/www/miq/vmdb/app/models/ems_refresh/refreshers/ems_refresher_mixin.rb:14:in `refresh'
/var/www/miq/vmdb/app/models/manageiq/providers/base_manager/refresher.rb:10:in `refresh'
/var/www/miq/vmdb/app/models/ems_refresh.rb:91:in `block in refresh'
/var/www/miq/vmdb/app/models/ems_refresh.rb:90:in `each'
/var/www/miq/vmdb/app/models/ems_refresh.rb:90:in `refresh'
/var/www/miq/vmdb/app/models/miq_queue.rb:347:in `block in deliver'
/opt/rh/rh-ruby23/root/usr/share/ruby/timeout.rb:91:in `block in timeout'
/opt/rh/rh-ruby23/root/usr/share/ruby/timeout.rb:33:in `block in catch'
/opt/rh/rh-ruby23/root/usr/share/ruby/timeout.rb:33:in `catch'
/opt/rh/rh-ruby23/root/usr/share/ruby/timeout.rb:33:in `catch'
/opt/rh/rh-ruby23/root/usr/share/ruby/timeout.rb:106:in `timeout'
/var/www/miq/vmdb/app/models/miq_queue.rb:343:in `deliver'
/var/www/miq/vmdb/app/models/miq_queue_worker_base/runner.rb:106:in `deliver_queue_message'
/var/www/miq/vmdb/app/models/miq_queue_worker_base/runner.rb:134:in `deliver_message'
/var/www/miq/vmdb/app/models/miq_queue_worker_base/runner.rb:152:in `block in do_work'
/var/www/miq/vmdb/app/models/miq_queue_worker_base/runner.rb:146:in `loop'
/var/www/miq/vmdb/app/models/miq_queue_worker_base/runner.rb:146:in `do_work'
/var/www/miq/vmdb/app/models/miq_worker/runner.rb:334:in `block in do_work_loop'
/var/www/miq/vmdb/app/models/miq_worker/runner.rb:331:in `loop'
/var/www/miq/vmdb/app/models/miq_worker/runner.rb:331:in `do_work_loop'
/var/www/miq/vmdb/app/models/miq_worker/runner.rb:153:in `run'
/var/www/miq/vmdb/app/models/miq_worker/runner.rb:128:in `start'
/var/www/miq/vmdb/app/models/miq_worker/runner.rb:21:in `start_worker'
/var/www/miq/vmdb/app/models/miq_worker.rb:343:in `block in start'
/opt/rh/cfme-gemset/gems/nakayoshi_fork-0.0.3/lib/nakayoshi_fork.rb:24:in `fork'
/opt/rh/cfme-gemset/gems/nakayoshi_fork-0.0.3/lib/nakayoshi_fork.rb:24:in `fork'
/var/www/miq/vmdb/app/models/miq_worker.rb:341:in `start'
/var/www/miq/vmdb/app/models/miq_worker.rb:270:in `start_worker'
/var/www/miq/vmdb/app/models/mixins/per_ems_worker_mixin.rb:68:in `start_worker_for_ems'
/var/www/miq/vmdb/app/models/mixins/per_ems_worker_mixin.rb:46:in `block in sync_workers'
/var/www/miq/vmdb/app/models/mixins/per_ems_worker_mixin.rb:45:in `each'
/var/www/miq/vmdb/app/models/mixins/per_ems_worker_mixin.rb:45:in `sync_workers'
/var/www/miq/vmdb/app/models/miq_server/worker_management/monitor.rb:53:in `block in sync_workers'
/var/www/miq/vmdb/app/models/miq_server/worker_management/monitor.rb:50:in `each'
/var/www/miq/vmdb/app/models/miq_server/worker_management/monitor.rb:50:in `sync_workers'
/var/www/miq/vmdb/app/models/miq_server/worker_management/monitor.rb:22:in `monitor_workers'
/var/www/miq/vmdb/app/models/miq_server.rb:346:in `block in monitor'
/var/www/miq/vmdb/gems/pending/util/extensions/miq-benchmark.rb:11:in `realtime_store'
/var/www/miq/vmdb/gems/pending/util/extensions/miq-benchmark.rb:30:in `realtime_block'
/var/www/miq/vmdb/app/models/miq_server.rb:346:in `monitor'
/var/www/miq/vmdb/app/models/miq_server.rb:368:in `block (2 levels) in monitor_loop'
/var/www/miq/vmdb/gems/pending/util/extensions/miq-benchmark.rb:11:in `realtime_store'
/var/www/miq/vmdb/gems/pending/util/extensions/miq-benchmark.rb:30:in `realtime_block'
/var/www/miq/vmdb/app/models/miq_server.rb:368:in `block in monitor_loop'
/var/www/miq/vmdb/app/models/miq_server.rb:367:in `loop'
/var/www/miq/vmdb/app/models/miq_server.rb:367:in `monitor_loop'
/var/www/miq/vmdb/app/models/miq_server.rb:250:in `start'
/var/www/miq/vmdb/lib/workers/evm_server.rb:65:in `start'
/var/www/miq/vmdb/lib/workers/evm_server.rb:92:in `start'
/var/www/miq/vmdb/lib/workers/bin/evm_server.rb:4:in `<main>'
[----] I, [2017-03-26T07:53:41.326671 #3019:110312c]  INFO -- : <AutomationEngine> Followed  Relationship [miqaedb:/System/Event/MiqEvent/POLICY/host_add_to_cluster#create]
[----] E, [2017-03-26T07:53:41.326703 #15256:110312c] ERROR -- : MIQ(ManageIQ::Providers::Redhat::InfraManager::Refresher#refresh) EMS: [RHEV-M (<RHV ip address>)], id: [3] Unable to perform refresh for the following targets:
[----] E, [2017-03-26T07:53:41.326877 #15256:110312c] ERROR -- : MIQ(ManageIQ::Providers::Redhat::InfraManager::Refresher#refresh)  --- ManageIQ::Providers::Redhat::InfraManager [RHEV-M (<RHV ip address>)] id [3]
[----] I, [2017-03-26T07:53:41.327119 #3019:110312c]  INFO -- : MIQ(MiqQueue#delivered) Message id: [41131], State: [ok], Delivered in [0.14786005] seconds
[----] I, [2017-03-26T07:53:41.328715 #3027:110312c]  INFO -- : <AutomationEngine> Followed  Relationship [miqaedb:/System/event_handlers/event_enforce_policy#create]
[----] I, [2017-03-26T07:53:41.329052 #3027:110312c]  INFO -- : <AutomationEngine> Followed  Relationship [miqaedb:/System/Event/MiqEvent/POLICY/host_remove_from_cluster#create]
[----] I, [2017-03-26T07:53:41.329481 #3027:110312c]  INFO -- : MIQ(MiqQueue#delivered) Message id: [41130], State: [ok], Delivered in [0.178560116] seconds
[----] I, [2017-03-26T07:53:41.330447 #15256:110312c]  INFO -- : MIQ(ManageIQ::Providers::Redhat::InfraManager::Refresher#refresh) Refreshing all targets...Complete
[----] E, [2017-03-26T07:53:41.330695 #15256:110312c] ERROR -- : MIQ(MiqQueue#deliver) Message id: [41123], Error: [Validation failed: Host Name has already been taken]

Version-Release number of selected component (if applicable):
CFME-5.7.2/RHV-4.0.5

How reproducible:
always

Expected results:
Refresh failure & it's reason should be displayed on CFME UI.