Fix an uninitialized variable error.
Fix an uninitialized variable error.

Found by: Coverity <http://scan.coverity.com/>
(CID: 77)

* subversion/libsvn_client/url.c
  (svn_client__derive_location): Initialize the cancelation function and baton
    for the case where they aren't user provided.

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