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.


git-svn-id: f8a4e5e023278da1e04e203c7fe051e3c4285d88@866936 13f79535-47bb-0310-9956-ffa450edef68

wbond/subversion,YueLinHo/Subversion,YueLinHo/Subversion,YueLinHo/Subversion,wbond/subversion,wbond/subversion,YueLinHo/Subversion,YueLinHo/Subversion,YueLinHo/Subversion,wbond/subversion,wbond/subversion,YueLinHo/Subversion,YueLinHo/Subversion,wbond/subversion,wbond/subversion