UI revert non-functional due to lack of sign-off

[autumnfound]

Reported by @chrisguindon yesterday while buzzing about working on the EF website commits. The issue occurs when using the Gerrit UI revert as there is no option to sign revert commits.

Included below is the message reported when attempting to revert:

Could not perform action: The contributor must sign-off on the contribution.:
  warning: subject >50 characters; use shorter first paragraph
  ----------
  Reviewing commit: ab708891
  Authored by: Christopher Guindon <chris.guindon@eclipse-foundation.org>
  Reviewing commit: ab7088916d8500deb63cd65516f8521d79316854
  Authored by: Christopher Guindon <chris.guindon@eclipse-foundation.org>
  The author is not a committer on the project.
  The author has a current Eclipse Contributor Agreement (ECA) on file.
  The author has not signed-off on the contribution.
If there are multiple commits, please ensure that each commit is signed-off.
  Please see http://wiki.eclipse.org/ECA

[autumnfound]

The current workaround would be to use local commits and reverts and sign them rather than use the UI. Some thought needs to go into the solution to make sure we aren't creating gaps