gerrit: Fix options for `gerrit ready`

`gerrit ready` is the CLI equivalent of commit-queue ready in the UI.
There is only CQ 0 or CQ +1, no CQ +2. Fix the options.

BUG=None
TEST=ran `gerrit help`

Change-Id: I5b3261a456cafeb9e3a9165b96120cff8009f65a
Reviewed-on: https://chromium-review.googlesource.com/513432
Commit-Ready: Kirtika Ruchandani <kirtika@chromium.org>
Tested-by: Kirtika Ruchandani <kirtika@chromium.org>
Reviewed-by: Mike Frysinger <vapier@chromium.org>
1 file changed