Add two more checks in ref-update.
Add two more checks in ref-update.

1. Check if the fixed/referenced issue IDs are non-zero.
2. Check if the commit is a revert one. If yes, skip the commit message check.

Change-Id: I1a3df857ec01fcb34e31241ba9ea4303106d4913
Signed-off-by: Wei Ren <88709af9b21626552153fb1f93c3f175914a23ee@smartconn.cc>

renweizhukov/gerrit-hooks