Add another svn auth failed string to check (older svn server version)

Found another string indicating failed authentication when using svn. The full message returned (urls masked) looks like this:

cmd: svn ls --verbose --non-interactive  'http://svn.host.com/svn/path'
response: svn: OPTIONS of 'http://svn.host.com/svn/path': authorization failed (http://svn.host.com)