Had to update a few tests, removed redundant code in gclient_scm_tests.

TEST=more readable unit tests
BUG=none

Review URL: http://codereview.chromium.org/3473003

git-svn-id: svn://svn.chromium.org/chrome/trunk/tools/depot_tools@59959 0039d316-1c4b-4281-b951-d872f2087c98