Replace ~/.git_template/commit_template and webapp/.git/hooks/prepare-commit-msg

commit_template

Test Plan:
# Commands to run, or process to follow to test the changes
#
# Previous commit:
#   {PREV_COMMIT_MSG}
# Review: {Dxxxx}
# can be used instead of 'Test Plan:' to continue that commit's Differential

prepare-commit-msg

#!/usr/bin/env python

import argparse
import subprocess
import re

def get_prev_commit_msg():
    return subprocess.check_output(['git', 'log', '-1', '--pretty=%B'])


def update_template(template):
    prev_msg = get_prev_commit_msg()
    summery = prev_msg.splitlines()[0]
    differential = re.findall("D\d\d\d\d+", prev_msg)
    if differential:
        revision = differential[0]
    else:
        revision = "Dxxxx"
    return template.format(PREV_COMMIT_MSG=summery,
                    Dxxxx=revision)

def main(commit_file):
    with open(commit_file, 'r') as f:
        template = f.read()
    template = update_template(template)
    with open(commit_file, 'w') as f:
        f.write(template)

if __name__ == "__main__":
    parser = argparse.ArgumentParser()
    # It takes one to three parameters. The first is the name of the
    # file that contains the commit log message. The second is the
    # source of the commit message, and can be: message (if a -m or
    # -F option was given); template (if a -t option was given or the
    # configuration option commit.template is set); merge (if the
    # commit is a merge or a .git/MERGE_MSG file exists); squash (if
    # a .git/SQUASH_MSG file exists); or commit, followed by a commit
    # SHA1 (if a -c, -C or --amend option was given).
    parser.add_argument('commit_msg_file',
                        help="The file to edit the commit msg of")
    parser.add_argument('kind',
                        help="I have no idea")
    parser.add_argument('commit', nargs='?',
                        help="SHA of amend or --commit type commits")
    args = parser.parse_args()
    if args.kind == 'template':
        main(args.commit_msg_file)