Description of problem:
a missing storage can cause cfme 5.5 to stop collecting data from openstack

Version-Release number of selected component (if applicable):
5.5.0.13

How reproducible:
too specific to reproduce entirely

Steps to Reproduce:
1. in openstack, fail to remove a stack (must end on an unknown error)
2. in cloudforms issue a refresh
3.

Actual results:
evm log :
[----] E, [2015-12-22T13:36:15.684101 #6625:80398c] ERROR -- : <Fog> excon.error     #<Excon::Errors::NotFound: Expected(200) <=> Actual(404 Not Found)
excon.error.response
  :body          => "404 Not Found\n\nThe resource could not be found.\n\n   "
  :headers       => {
    "Content-Length"         => "52"
    "Content-Type"           => "text/plain; charset=UTF-8"
    "Date"                   => "Tue, 22 Dec 2015 13:39:17 GMT"
    "X-Openstack-Request-Id" => "req-3a18cbfd-820b-4cf6-ad72-cd507ffa0afe"
  }
  :local_address => "172.22.32.103"
  :local_port    => 44299
  :reason_phrase => "Not Found"
  :remote_ip     => "172.22.224.17"
  :status        => 404
  :status_line   => "HTTP/1.1 404 Not Found\r\n"
>

[----] E, [2015-12-22T13:36:15.692418 #6625:80398c] ERROR -- : <Fog> excon.error     #<Excon::Errors::NotFound: Expected(200) <=> Actual(404 Not Found)
excon.error.response
  :body          => "404 Not Found\n\nThe resource could not be found.\n\n   "
  :headers       => {
    "Content-Length"         => "52"
    "Content-Type"           => "text/plain; charset=UTF-8"
    "Date"                   => "Tue, 22 Dec 2015 13:39:17 GMT"
    "X-Openstack-Request-Id" => "req-60dd9b18-599c-428f-b387-4062e2a545c0"
  }
  :local_address => "172.22.32.103"
  :local_port    => 44300
  :reason_phrase => "Not Found"
  :remote_ip     => "172.22.224.17"
  :status        => 404
  :status_line   => "HTTP/1.1 404 Not Found\r\n"
>

[----] E, [2015-12-22T13:36:15.700585 #6625:80398c] ERROR -- : <Fog> excon.error     #<Excon::Errors::NotFound: Expected(200) <=> Actual(404 Not Found)
excon.error.response
  :body          => "404 Not Found\n\nThe resource could not be found.\n\n   "
  :headers       => {
    "Content-Length"         => "52"
    "Content-Type"           => "text/plain; charset=UTF-8"
    "Date"                   => "Tue, 22 Dec 2015 13:39:17 GMT"
    "X-Openstack-Request-Id" => "req-a84d1b46-edfa-4dad-be8b-410b8acbdbd7"
  }
  :local_address => "172.22.32.103"
  :local_port    => 44301
  :reason_phrase => "Not Found"
  :remote_ip     => "172.22.224.17"
  :status        => 404
  :status_line   => "HTTP/1.1 404 Not Found\r\n"
>

[----] D, [2015-12-22T13:36:16.630988 #6625:80398c] DEBUG -- : MIQ(ManageIQ::Providers::Openstack::InfraManager::Refresher#refresh) EMS: [Openstack Beta undercloud], id: [99000000000005] Parsing Openstack inventory...Completed in 104.101
502848 seconds

no stats seem to be captured by openstack,  monitoring of the environment completely stopped


Expected results:
warnings issued but monitoring (capture ofdata for other stacks) is still performed

Additional info:
the customer reported that the removal of the stack that was causing the issue solved the problem but they are concerned that the presence of such an anomaly can stop entirely the capture of data from the openstack environment.