Currently checkpatch.pl does not recognize git's default commit revert
message and will complain about the hash format.  Add special audit for
revert commit message line to fix it.

Link: http://lkml.kernel.org/r/20170411191532.74381-1-wvw@google.com


Signed-off-by: Wei Wang <wvw@google.com>
Acked-by: Joe Perches <joe@perches.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>