If the keyring password doesn't work on the first try, it probably won't
work on the second or third. The KeyringCreds object already supports
this, we just were recreating the object at each step.

Also, if after three tries authentication to code.google.com still
fails, then the script should continue and just use un-authenticated
access to code.google.com.

BUG=158388


Review URL: https://chromiumcodereview.appspot.com/11340023

git-svn-id: svn://svn.chromium.org/chrome/trunk/tools/depot_tools@165446 0039d316-1c4b-4281-b951-d872f2087c98