Description of problem: Rollup messages for class MiqRegion are consistently failing


Version-Release number of selected component (if applicable):
5.5.0.9-beta2

How reproducible: start C&U and wait for MiqRegion rollups scheduled to begin


Steps to Reproduce:
1.
2.
3.

Actual results:
message terminates in error


Expected results:
rollups should complete without error.

Additional info:
full log sequence from failing rollup message processing:
=====
[----] I, [2015-11-08T18:22:48.002377 #22633:99b998]  INFO -- : MIQ(MiqEmsMetricsProcessorWorker::Runner#get_message_via_drb) Message id: [441000000363311], MiqWorker id: [441000000002068], Zone: [default], Role: [ems_metrics_processor], Server: [], Ident: [ems_metrics_processor], Target id: [], Instance id: [441000000000001], Task id: [], Command: [MiqRegion.perf_rollup], Timeout: [1800], Priority: [100], State: [dequeue], Deliver On: [2015-11-08 23:00:00 UTC], Data: [], Args: ["2015-11-08T22:00:00Z", "hourly"], Dequeued in: [3.183835599] seconds
[----] I, [2015-11-08T18:22:48.045191 #22633:99b998]  INFO -- : MIQ(MiqRegion#perf_rollup) [hourly] Rollup for MiqRegion name: [Region 441], id: [441000000000001] for time: [2015-11-08T22:00:00Z]...
[----] E, [2015-11-08T18:22:48.602061 #22633:99b998] ERROR -- : MIQ(MiqQueue#deliver) Message id: [441000000363311], Error: [Association named 'hosts' was not found on MiqRegion; perhaps you misspelled it?]
[----] E, [2015-11-08T18:22:48.602407 #22633:99b998] ERROR -- : [ActiveRecord::AssociationNotFoundError]: Association named 'hosts' was not found on MiqRegion; perhaps you misspelled it?  Method:[rescue in deliver]
[----] E, [2015-11-08T18:22:48.602775 #22633:99b998] ERROR -- : /opt/rh/cfme-gemset/bundler/gems/rails-a37d0e57571f/activerecord/lib/active_record/associations.rb:161:in `association'
/opt/rh/cfme-gemset/bundler/gems/rails-a37d0e57571f/activerecord/lib/active_record/associations/builder/collection_association.rb:66:in `host_ids'
/var/www/miq/vmdb/app/models/mixins/aggregation_mixin.rb:107:in `aggregate_hardware'
/var/www/miq/vmdb/app/models/mixins/aggregation_mixin.rb:35:in `aggregate_cpu_speed'
/var/www/miq/vmdb/app/models/vim_performance_state.rb:131:in `capture_total'
/var/www/miq/vmdb/app/models/vim_performance_state.rb:60:in `capture'
/var/www/miq/vmdb/app/models/metric/ci_mixin/capture.rb:209:in `perf_capture_state'
/var/www/miq/vmdb/app/models/metric/ci_mixin/state_finders.rb:21:in `vim_performance_state_for_ts'
/var/www/miq/vmdb/app/models/metric/ci_mixin/state_finders.rb:41:in `ext_management_systems_from_vim_performance_state_for_ts'
/var/www/miq/vmdb/app/models/metric/rollup.rb:189:in `rollup_child_metrics'
/var/www/miq/vmdb/app/models/metric/rollup.rb:131:in `block in rollup_hourly'
/var/www/miq/vmdb/app/models/metric/rollup.rb:131:in `each'
/var/www/miq/vmdb/app/models/metric/rollup.rb:131:in `rollup_hourly'
/var/www/miq/vmdb/app/models/metric/ci_mixin/rollup.rb:91:in `block (2 levels) in perf_rollup'
/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/metric/ci_mixin/rollup.rb:90:in `block in perf_rollup'
/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/metric/ci_mixin/rollup.rb:77:in `perf_rollup'
/var/www/miq/vmdb/app/models/miq_queue.rb:345:in `block in deliver'
/opt/rh/rh-ruby22/root/usr/share/ruby/timeout.rb:89:in `block in timeout'
/opt/rh/rh-ruby22/root/usr/share/ruby/timeout.rb:34:in `block in catch'
/opt/rh/rh-ruby22/root/usr/share/ruby/timeout.rb:34:in `catch'
/opt/rh/rh-ruby22/root/usr/share/ruby/timeout.rb:34:in `catch'
/opt/rh/rh-ruby22/root/usr/share/ruby/timeout.rb:104:in `timeout'
/var/www/miq/vmdb/app/models/miq_queue.rb:341: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:151:in `block in do_work'
/var/www/miq/vmdb/app/models/miq_queue_worker_base/runner.rb:145:in `loop'
/var/www/miq/vmdb/app/models/miq_queue_worker_base/runner.rb:145:in `do_work'
/var/www/miq/vmdb/app/models/miq_worker/runner.rb:323:in `block in do_work_loop'
/var/www/miq/vmdb/app/models/miq_worker/runner.rb:320:in `loop'
/var/www/miq/vmdb/app/models/miq_worker/runner.rb:320:in `do_work_loop'
/var/www/miq/vmdb/app/models/miq_worker/runner.rb:142:in `run'
/var/www/miq/vmdb/app/models/miq_worker/runner.rb:123:in `start'
/var/www/miq/vmdb/app/models/miq_worker/runner.rb:24:in `start_worker'
/var/www/miq/vmdb/lib/workers/bin/worker.rb:2:in `<top (required)>'
/opt/rh/cfme-gemset/bundler/gems/rails-a37d0e57571f/railties/lib/rails/commands/runner.rb:60:in `load'
/opt/rh/cfme-gemset/bundler/gems/rails-a37d0e57571f/railties/lib/rails/commands/runner.rb:60:in `<top (required)>'
/opt/rh/cfme-gemset/bundler/gems/rails-a37d0e57571f/railties/lib/rails/commands/commands_tasks.rb:123:in `require'
/opt/rh/cfme-gemset/bundler/gems/rails-a37d0e57571f/railties/lib/rails/commands/commands_tasks.rb:123:in `require_command!'
/opt/rh/cfme-gemset/bundler/gems/rails-a37d0e57571f/railties/lib/rails/commands/commands_tasks.rb:90:in `runner'
/opt/rh/cfme-gemset/bundler/gems/rails-a37d0e57571f/railties/lib/rails/commands/commands_tasks.rb:39:in `run_command!'
/opt/rh/cfme-gemset/bundler/gems/rails-a37d0e57571f/railties/lib/rails/commands.rb:17:in `<top (required)>'
/var/www/miq/vmdb/bin/rails:4:in `require'
/var/www/miq/vmdb/bin/rails:4:in `<main>'
[----] I, [2015-11-08T18:22:48.603324 #22633:99b998]  INFO -- : MIQ(MiqQueue#delivered) Message id: [441000000363311], State: [error], Delivered in [0.60054032] seconds
=====