The majority of chromium projects are on googlesource.com, which can
display a range of commits on the web. Use this feature instead of
dumping logs into the commit message.

Particularly, this avoids creating large commit messages as these logs
sometimes contain upwards of 50 commits.

Review URL: https://codereview.chromium.org/1257233006

git-svn-id: svn://svn.chromium.org/chrome/trunk/tools/depot_tools@296184 0039d316-1c4b-4281-b951-d872f2087c98