Skip clusters with invalid configuration

[agrare]

If a cluster doesn't have a valid configuration skip it, otherwise the refresh will fail with the following error:

[----] E, [2017-03-28T10:04:08.508023 #29777:107b13c] ERROR -- : MIQ(ManageIQ::Providers::Vmware::InfraManager::Refresher#refresh) EMS: [VMWare], id: [10000000000004] Refresh failed
[----] E, [2017-03-28T10:04:08.509412 #29777:107b13c] ERROR -- : [NoMethodError]: undefined method `[]' for nil:NilClass  Method:[rescue in block in refresh]
[----] E, [2017-03-28T10:04:08.509604 #29777:107b13c] ERROR -- : /var/www/miq/vmdb/app/models/manageiq/providers/vmware/infra_manager/refresh_parser.rb:1296:in `block in cluster_inv_to_hashes'
/var/www/miq/vmdb/app/models/manageiq/providers/vmware/infra_manager/refresh_parser.rb:1292:in `each'
/var/www/miq/vmdb/app/models/manageiq/providers/vmware/infra_manager/refresh_parser.rb:1292:in `cluster_inv_to_hashes'
/var/www/miq/vmdb/app/models/manageiq/providers/vmware/infra_manager/refresh_parser.rb:15:in `ems_inv_to_hashes'
/var/www/miq/vmdb/app/models/manageiq/providers/vmware/infra_manager/refresher.rb:48:in `block in parse_targeted_inventory'

https://bugzilla.redhat.com/show_bug.cgi?id=1436853

[miq-bot]

Checked commit agrare@0ba0091 with ruby 2.2.6, rubocop 0.47.1, and haml-lint 0.20.0
1 file checked, 0 offenses detected
Everything looks good. 🍪

[simaishi]

Fine backport details:

$ git log -1
commit 89be6564916e4ee012d9c013dba7d695df7d1da6
Author: Greg Blomquist <blomquisg@gmail.com>
Date:   Thu Apr 6 15:52:04 2017 -0400

    Merge pull request #36 from agrare/bz_1436853_cluster_invalid_configuration
    
    Skip clusters with invalid configuration
    (cherry picked from commit f602e32f61cd3a3d3e67e549971c3dcb14d7b28a)
    
    https://bugzilla.redhat.com/show_bug.cgi?id=1439944

[simaishi]

Euwe backport (to manageiq repo) details:

$ git log -1
commit f3b4ded7d63b355665723c860036d42071233bf8
Author: Greg Blomquist <blomquisg@gmail.com>
Date:   Thu Apr 6 15:52:04 2017 -0400

    Merge pull request #36 from agrare/bz_1436853_cluster_invalid_configuration
    
    Skip clusters with invalid configuration
    (cherry picked from commit f602e32f61cd3a3d3e67e549971c3dcb14d7b28a)
    
    https://bugzilla.redhat.com/show_bug.cgi?id=1439945