Description of problem:
If a changeset is in the middle of being promoted, user can click through the "Promoting..." text/link to view the changeset and click the "Promote" button again.  If something is in the process of being promoted, it makes sense that the button shouldn't be enabled for continued attempts until this one passes/fails

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


How reproducible:


Steps to Reproduce:
1.  Sync RH content
2.  Create a new changeset, "Test Changeset"
3.  Add content to the changeset; review and Promote content
4.  On resulting UI, note "Promoting... Test Changeset"; click this text to view the Changeset details
5. Observe menu bar at bottom; click "Promote"
  
Actual results:
Button is clickable

Expected results:
Probably should not be clickable if it is already in process.

Additional info:

I am not sure if this can trigger a race condition or not - unsure whether there are safeguards in place to prevent - but it seems it shouldn't be enabled in the first place.