Adding Owners-Override to gerrit CLI

Adds CLI support to apply the Owners-Override label when scripting large
scale refactors (e.g. across every src/project repo).

BUG=b:195297624
TEST=run

Change-Id: I85eac9b04cff803ab0f9a762f0cc4c9b0d79edc7
Reviewed-on: https://chromium-review.googlesource.com/c/chromiumos/chromite/+/3064255
Tested-by: C Shapiro <shapiroc@chromium.org>
Auto-Submit: C Shapiro <shapiroc@chromium.org>
Reviewed-by: Andrew Lamb <andrewlamb@chromium.org>
Commit-Queue: Andrew Lamb <andrewlamb@chromium.org>
diff --git a/scripts/gerrit.py b/scripts/gerrit.py
index db54509..8ce6693 100644
--- a/scripts/gerrit.py
+++ b/scripts/gerrit.py
@@ -558,6 +558,13 @@
   LABEL = 'Commit-Queue'
   VALUES = ('0', '1', '2')
 
+class ActionLabelOwnersOverride(_ActionLabeler):
+  """Change the Owners-Override label (1=Override)"""
+
+  COMMAND = 'label-oo'
+  LABEL = 'Owners-Override'
+  VALUES = ('0', '1')
+
 
 class _ActionSimpleParallelCLs(UserAction):
   """Base helper for actions that only accept CLs."""