Make sure every site that catches gclient_utils.Error also catch
subprocess2.CalledProcessError.

BUG=
TEST=

Review URL: http://codereview.chromium.org/6691034

git-svn-id: svn://svn.chromium.org/chrome/trunk/tools/depot_tools@80339 0039d316-1c4b-4281-b951-d872f2087c98