Revision 1684047

Avoid callers of svn__compress() and svn__decompress() construct fake
svn_stringbuf_t instance.

* subversion/include/private/svn_subr_private.h
* subversion/libsvn_subr/compress.c
  (svn__compress, svn__decompress): Replace IN parameter of type 
   svn_stringbuf_t with DATA/LEN.

* subversion/libsvn_delta/svndiff.c
  (zlib_decode): Remove.
  (window_handler): Just pass DATA/LEN to svn__compress() instead of
   construction fake svn_stringbuf_t.
  (decode_window): Call svn__decompress() directly without zlib_decode()
   helper.

* subversion/libsvn_fs_fs/revprops.c
  (parse_packed_revprops, repack_revprops, svn_fs_fs__copy_revprops):
   Adapt calls to svn__compress() and svn__decompress().
* subversion/libsvn_fs_x/revprops.c
  (parse_packed_revprops, repack_revprops, svn_fs_fs__copy_revprops):
   Adapt calls to svn__compress() and svn__decompress().
* subversion/libsvn_subr/packed_data.c
  (write_stream_data, read_stream_data): Adapt calls to
   svn__compress() and svn__decompress().