Follow-up to r1449764: Fix a crash due to an uninitialised variable.

* subversion/svn/conflict-callbacks.c
  (handle_tree_conflict): Use the default tree conflict menu with update/switch
   if none of the special-case menus applies.


git-svn-id: https://svn.apache.org/repos/asf/subversion/trunk@1449768 13f79535-47bb-0310-9956-ffa450edef68