Break out the export directory functionality into a helper function.
Break out the export directory functionality into a helper function.

* subversion/libsvn_client/export.c
  (export_directory): New.
  (svn_client_export5): Call the above helper.


git-svn-id: f8a4e5e023278da1e04e203c7fe051e3c4285d88@1417266 13f79535-47bb-0310-9956-ffa450edef68

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