* subversion/libsvn_client/switch.c (svn_client_switch): Return an   error if attempting to switch something that does not have an URL.   Tweak existing error message.
* subversion/libsvn_client/switch.c (svn_client_switch): Return an
  error if attempting to switch something that does not have an URL.
  Tweak existing error message.


git-svn-id: f8a4e5e023278da1e04e203c7fe051e3c4285d88@843334 13f79535-47bb-0310-9956-ffa450edef68

YueLinHo/Subversion,wbond/subversion,YueLinHo/Subversion,wbond/subversion,YueLinHo/Subversion,YueLinHo/Subversion,YueLinHo/Subversion,wbond/subversion,wbond/subversion,YueLinHo/Subversion,wbond/subversion,YueLinHo/Subversion,YueLinHo/Subversion,wbond/subversion,wbond/subversion