Support for vm / orch. stack / instance / service unretire

[mzazrivec]

1. have a retired vm
2. go to that vm's details page and hit 'Set retirement date' button
3. click on the input field (it render the datetimepicker widget & clear the input field)
4. Save button should become available

https://bugzilla.redhat.com/show_bug.cgi?id=1534962

[miq-bot]

Checked commit mzazrivec@8fbf835 with ruby 2.3.3, rubocop 0.52.0, haml-lint 0.20.0, and yamllint 1.10.0
0 files checked, 0 offenses detected
Everything looks fine. 🍰

[JPrause]

@mzazrivec who can help review this PR?

[mzazrivec]

@himdel Perhaps?

[himdel]

LGTM, verified clicking the datepicker when the date is invalid (in the past) makes the save button enabled.

Nothing else seems to break and the change should be harmless 👍

(Still wondering how to reach this bug in production though, since the VM will already have been retired :))

(waiting for travis)

[simaishi]

Gaprindashvili backport details:

$ git log -1
commit 4e81fe24379c8abdd9f41bc71a8df6bb45a22a75
Author: Martin Hradil <[email protected]>
Date:   Tue Feb 20 16:56:37 2018 +0000

    Merge pull request #3428 from mzazrivec/support_for_unretire
    
    Support for vm / orch. stack / instance / service unretire
    (cherry picked from commit 4ec02e58f338ea51b47fd77814379ad75c09786a)
    
    https://bugzilla.redhat.com/show_bug.cgi?id=1553243