Fix bug introduced in r26803.
Fix bug introduced in r26803.

* subversion/libsvn_client/merge.c
  (drive_merge_report_editor): Call svn_client__get_diff_editor with 
   same 'start rev' as that we use with 'reporter->set_path("")'.
 
Found by: Senthil Kumaran S <senthil@collab.net>

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