Description of problem:
- Unable to schedule an NFS or Samba Database Backup.
- Though the URI for the backup is correctly specified in the 'uri' field, it does not accept the Schedule request.
- It does not display error on the CloudForms UI But, it does flash an error in production.log as below
`Validation failed: FileDepotSmb: Uri can't be blank`

Version-Release number of selected component (if applicable):
CloudForms Management Engine 5.10

How reproducible:
Every time while adding a schedule for database backup

Steps to Reproduce:
1. Setup a CloudForms Management Engine 5.10
2. Try adding the Database Backup for NFS or Samba
3. Fill in all the details
4. Press the Add button

Actual results:
It just refreshes the page and does not accept the Schedule Request.

Expected results:
It should accept the Schedule Request as it used to in previous versions

Error that flash in production.log:
[----] I, [2019-02-18T05:00:42.896290 #5131:d7e7a4]  INFO -- : Started POST "/ops/schedule_edit/1000000000027?button=save" for 127.0.0.1 at 2019-02-18 05:00:42 -0500
[----] I, [2019-02-18T05:00:42.902022 #5131:d7e7a4]  INFO -- : Processing by OpsController#schedule_edit as JS
[----] I, [2019-02-18T05:00:42.902316 #5131:d7e7a4]  INFO -- :   Parameters: {"action_typ"=>"db_backup", "depot_name"=>"any", "filter_typ"=>"", "log_userid"=>"", "log_aws_region"=>"", "openstack_region"=>"", "keystone_api_version"=>"", "v3_domain_ident"=>"", "swift_api_port"=>"5000", "security_protocol"=>"", "log_protocol"=>"Network File System", "description"=>"try", "enabled"=>"true", "name"=>"try", "timer_typ"=>"Once", "timer_value"=>"0", "start_date"=>"Mon Feb 18 2019 00:00:00 GMT+0530 (IST)", "start_hour"=>"16", "start_min"=>"0", "time_zone"=>"Kolkata", "uri"=>"vault.xxxx.x.x.x.x./xxx/", "uri_prefix"=>"nfs", "filter_value"=>"", "log_password"=>"[FILTERED]", "button"=>"save", "id"=>"1000000000027"}
[----] F, [2019-02-18T05:00:42.921079 #5131:d7e7a4] FATAL -- : Error caught: [ActiveRecord::RecordInvalid] Validation failed: FileDepotNfs: Uri can't be blank
/opt/rh/cfme-gemset/gems/activerecord-5.0.7.1/lib/active_record/validations.rb:78:in `raise_validation_error'
/opt/rh/cfme-gemset/gems/activerecord-5.0.7.1/lib/active_record/validations.rb:50:in `save!'