Change to the new wording according to Arm corp:
https://mails.dpdk.org/archives/dev/2018-October/115174.html
otherwise, "Wrong headline lowercase" may be falsely reported.
Fixes: f146ada21d1e ("scripts: add more git log checks")
Cc: stable@dpdk.org
Signed-off-by: Gavin Hu <gavin.hu@arm.com>
Acked-by: Jerin Jacob <jerinj@marvell.com>