Fix issue #4079 ("svnmucc cp rev arg" SEGV).
Fix issue #4079 ("svnmucc cp rev arg" SEGV).

* subversion/svnmucc/svnmucc.c
  (main): Fix the conditional which checks for a shortage of URL arguments.


git-svn-id: f8a4e5e023278da1e04e203c7fe051e3c4285d88@1407597 13f79535-47bb-0310-9956-ffa450edef68

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