Xcode 4.3 git returns the version like below:

git version 1.7.7.5 (Apple Git-26)

Modify GIT.AssertVersion to accept such input.

Also modify tests/gclient_scm_test.py to pass tests, but not sure
the fix is collect.

BUG=chromium:115576
TEST=ran tests/gclient_scm_test.py

Review URL: http://codereview.chromium.org/9443047

git-svn-id: svn://svn.chromium.org/chrome/trunk/tools/depot_tools@123399 0039d316-1c4b-4281-b951-d872f2087c98