Remove some unused code in 'svn'.

* subversion/svn/cl.h,
  subversion/svn/notify.c
  (svn_cl__notifier_reset_conflict_stats): Delete this unused function.

* subversion/svn/resolve-cmd.c
  (svn_cl__resolve): Don't re-install the conflict resolver callback, since
    the one and only callback is already installed.


git-svn-id: https://svn.apache.org/repos/asf/subversion/trunk@1471443 13f79535-47bb-0310-9956-ffa450edef68