Following up on r1668595, fix textual argument reference.
Following up on r1668595, fix textual argument reference.

Found by: julianfoad

* subversion/svn/diff-cmd.c
  (svn_cl__diff): Pass right argument name to error function.


git-svn-id: f8a4e5e023278da1e04e203c7fe051e3c4285d88@1668604 13f79535-47bb-0310-9956-ffa450edef68

YueLinHo/Subversion,YueLinHo/Subversion,YueLinHo/Subversion,YueLinHo/Subversion,YueLinHo/Subversion,YueLinHo/Subversion,YueLinHo/Subversion,YueLinHo/Subversion