Avoid a potential infinite loop when using SASL authentication and the server returns an error before the client prompts the user for credentials.  This can happen with e.g. NTLM.
Avoid a potential infinite loop when using SASL authentication and the server
returns an error before the client prompts the user for credentials.  This can
happen with e.g. NTLM.

Found by: djh

* subversion/libsvn_ra_svn/cyrus_auth.c
  (cred_baton_t): New boolean field 'was_used'.
  (get_credentials): Set baton->was_used to TRUE.
  (svn_ra_svn__do_cyrus_auth): If authentication failed but our username and
   password callbacks were never invoked, don't retry authentication, just
   return the error we got from the server.

jmckaskill/subversion,jmckaskill/subversion,jmckaskill/subversion,jmckaskill/subversion,jmckaskill/subversion,jmckaskill/subversion,jmckaskill/subversion,jmckaskill/subversion