Fix issue #4513: 'svn auth' shouldn't treat argv patterns as URLs.

* subversion/svn/auth-cmd.c
  (svn_cl__auth): Convert arguments to UTF-8 but otherwise leave them
   unchanged. Prevents patterns from being mangled by URL canonicalisation.


git-svn-id: https://svn.apache.org/repos/asf/subversion/trunk@1629616 13f79535-47bb-0310-9956-ffa450edef68