* subversion/svn/conflict-callbacks.c
  (handle_text_conflict): If the user picks the "m" option and
   the external merge tool fails, don't fall back to the internal
   merge tool but show the conflict prompt again so the user can
   decide how to proceed.

Suggested by: breser


git-svn-id: https://svn.apache.org/repos/asf/subversion/trunk@1589707 13f79535-47bb-0310-9956-ffa450edef68