Fix the crash Sussman was seeing after revision 4948.
Fix the crash Sussman was seeing after revision 4948.

* subversion/libsvn_wc/providers.c
  (get_creds): initialize susername and spassword to NULL, so we can later 
   test them for validity to see if we should use their data.

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