Set max commit summary lengths for Gerrit

This doesn't block them from being submitted, but will provide
feedback to the user when they've got a super long line. The
defaults are too narrow and will annoy more people than they
help, but we can at least let people know when their commit
message is really long.

Change-Id: I2df7f2c911788d01a8873f89e1cd4890f7d7f125