Backport r1525902: issues #4428, #4429: external points at redirected URL.
Backport r1525902: issues #4428, #4429: external points at redirected URL.

* subversion/libsvn_client/externals.c
  (handle_external_item_change):
    Pass the possibly redirected URL to switch_dir_external(), not the old one.


git-svn-id: 6fa99006578fc44b94151d3d70effe55ea8e554f@1525914 13f79535-47bb-0310-9956-ffa450edef68

wbond/subversion,wbond/subversion,wbond/subversion,wbond/subversion,wbond/subversion,wbond/subversion,wbond/subversion