Should allow more than 50 characters in commit message for docs project

50 characters for commit message is a bit too limiting to fail a patch checkin.

Note these 2 patches:

66521: https://git.opendaylight.org/gerrit/#/c/66521/

66520: https://git.opendaylight.org/gerrit/#/c/66520/

66521 does not have the commit message length check in daexim and it passes, but 66520 fails because of this commit message check.

The number of characters allowed in commit message needs to be extended to something like 72.