We appear to be getting 403's when encountering errors other than mismatched
credentials.  The error message was originally hidden to avoid clutter, but it
has become obvious that there are other transient errors hidden behind a 403.

This change prints the original gsutil error message regardless of whether or not
we enconter a 403 or 404.


BUG=

Review URL: https://chromiumcodereview.appspot.com/23484061

git-svn-id: svn://svn.chromium.org/chrome/trunk/tools/depot_tools@224195 0039d316-1c4b-4281-b951-d872f2087c98