Fix multi-target Set Ownership

[himdel]

Since #1578, when doing Set Ownership over multiple items:

• set user to a User, set group to dont-change
  ... user gets set to User, and group gets reset to nil

• set group to a Group, set user to dont-change
  ... group gets set to Group, and user gets reset to nil

This makes sure we don't reset groups or users unless asked to.

Fixes https://bugzilla.redhat.com/show_bug.cgi?id=1657260

---

The difference is that...

Vm.set_ownership([123], {:user => (User)} only changes user,
but Vm.set_ownership([123], {:user => (User), :group => nil} updates both.

[himdel]

Aaand added a spec:

(fails without the fix:

         expected: ([71000000000176], {:group=>nil})
              got: ([71000000000176], {:owner=>nil, :group=>nil})

)

[miq-bot]

Checked commits https://github.com/himdel/manageiq-ui-classic/compare/b5c08fde841963ee07b663c1b071f99ee1cb1b0d~...3d8c0ef5f855e9da9bed443327f4198f162cf289 with ruby 2.3.3, rubocop 0.52.1, haml-lint 0.20.0, and yamllint 1.10.0
2 files checked, 4 offenses detected

spec/controllers/vm_infra_controller_spec.rb

• ❗ - Line 411, Col 69 - Style/BracesAroundHashParameters - Redundant curly braces around a hash parameter.
• ❗ - Line 413, Col 9 - Layout/AlignHash - Align the elements of a hash literal if they span more than one line.
• ❗ - Line 414, Col 9 - Layout/AlignHash - Align the elements of a hash literal if they span more than one line.
• ❗ - Line 416, Col 9 - Layout/AlignHash - Align the elements of a hash literal if they span more than one line.

[himdel]

(specs should go green after #5065)

[Hyperkid123]

Tested in UI. Fixes the issue.

[simaishi]

Hammer backport details:

$ git log -1
commit 848e3294fd46bd4d5907900d250e5a8308578d05
Author: Milan Zázrivec <mzazrivec@redhat.com>
Date:   Mon Dec 10 09:51:49 2018 +0100

    Merge pull request #5064 from himdel/ownership
    
    Fix multi-target Set Ownership
    
    (cherry picked from commit 91bacce0abaad57424741dcff4653133e2f0b352)
    
    Fixes https://bugzilla.redhat.com/show_bug.cgi?id=1657260

[simaishi]

Gaprindashvili backport details:

$ git log -1
commit 3239ca073c8d13bcf707215adb0393078198a2f5
Author: Milan Zázrivec <mzazrivec@redhat.com>
Date:   Mon Dec 10 09:51:49 2018 +0100

    Merge pull request #5064 from himdel/ownership
    
    Fix multi-target Set Ownership
    
    (cherry picked from commit 91bacce0abaad57424741dcff4653133e2f0b352)
    
    Fixes https://bugzilla.redhat.com/show_bug.cgi?id=1657939