Implement readline handlers for a couple of our existing streams.
Implement readline handlers for a couple of our existing streams.

* subversion/libsvn_subr/stream.c
  (readline_handler_disown, readline_handler_stringbuf,
   readline_handler_string, readline_handler_lazyopen): New.
  (svn_stream_disown, svn_stream_from_stringbuf,
   svn_stream_from_string, svn_stream_lazyopen_create): Set new handlers.


git-svn-id: f8a4e5e023278da1e04e203c7fe051e3c4285d88@1758981 13f79535-47bb-0310-9956-ffa450edef68

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