Fix a possible crash in ra_svn if SASL authentication is active.
Fix a possible crash in ra_svn if SASL authentication is active.

* subversion/libsvn_ra_svn/cyrus_auth.c
  (svn_ra_svn__do_cyrus_auth): Give the auth callbacks sufficient
   lifetime to survive until connection pool cleanup. CyrusSASL
   needs the callbacks in the cleanup handler of this pool.
   
Found by: Dave Huang <khym@azeotrope.org>


git-svn-id: f8a4e5e023278da1e04e203c7fe051e3c4285d88@1166555 13f79535-47bb-0310-9956-ffa450edef68

YueLinHo/Subversion,YueLinHo/Subversion,YueLinHo/Subversion,YueLinHo/Subversion,YueLinHo/Subversion,YueLinHo/Subversion,YueLinHo/Subversion,YueLinHo/Subversion