Don't expose /COMMIT_MSG as a modified file in ChangeData

We don't want uses to pattern match "file:^/COMMIT_MSG", because
every single change contains it.

Change-Id: Ib47af2ad97950d7a3f7326d743a9b01fb11866d4
Signed-off-by: Shawn O. Pearce <sop@google.com>
2 files changed