* subversion/svn/conflict-callbacks.c   (open_editor): Print the root cause of errors when the external editor    fails to run, so we print the proper message if error tracing is enabled.    Equivalent of what r1358117 did to the built-in merge tool.
* subversion/svn/conflict-callbacks.c
  (open_editor): Print the root cause of errors when the external editor
   fails to run, so we print the proper message if error tracing is enabled.
   Equivalent of what r1358117 did to the built-in merge tool.

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