mod_dav_svn: Use compressed svndiff1 deltas when delivering replay reports, if the client supports them.
Previously, such reports have always been using uncompressed svndiff0 format for deltas, even if the client has indicated that it would like to see svndiff1 via the "Accept-Encoding" header. Compression can have a noticeable performance impact over WAN or thin networks.
* subversion/mod_dav_svn/reports/replay.c (struct edit_baton_t): Add new 'svndiff_version' field. (dav_svn__replay_report): Pass the negotiated svndiff version to ... (make_editor): ...this function that constructs an edit baton. (apply_textdelta): Use the negotiated svndiff version for deltas.