If the key is consistency, use present tense. If you consistently use past tense, that works until your team merges with another one that's more conventional.
The commit message is the headline of your story. Headlines are in present tense even though they describe past events.
Honestly, out of all the things people argue about this has always struck me the strangest. It's the part that makes the least real world difference (vs not including ticket numbers - for example) yet it seems to be the thing people get the most impassioned about.
Consistency is important, but if you're expending more energy arguing about it than you would deciphering past tense message then you have serious questions to ask yourself. :P
The commit message is the headline of your story. Headlines are in present tense even though they describe past events.