Also, modify git-cl to also update depot_tools. Otherwise, the git-cl
script never gets updated for folks that only use git-cl but
not gclient. This fixes a bug ChromiumOS developers are currently seeing
where there git-cl checkout is still pointing to src.chromium.org
and not git.chromium.org.

BUG=none
TEST=Verified that git-cl help and gclient help work.

Review URL: http://codereview.chromium.org/3817011

git-svn-id: svn://svn.chromium.org/chrome/trunk/tools/depot_tools@62948 0039d316-1c4b-4281-b951-d872f2087c98