Add missing newline to the message when doing propset
on a nonexisting file.

* subversion/svn/notify.c
  (notify): Add missing newline, keeping the string itself
   intact to be nice to the translators.

Approved by: breser


git-svn-id: https://svn.apache.org/repos/asf/subversion/trunk@1467803 13f79535-47bb-0310-9956-ffa450edef68