Associate .flac to raw muxer

Signed-off-by: Rafaël Carré <rafael.carre@gmail.com>
(cherry picked from commit c47bb3b7)
Signed-off-by: Jean-Baptiste Kempf <jb@videolan.org>

modules/stream_out/standard.c

@@ -250,6 +250,7 @@ static int Open( vlc_object_t *p_this )
             { "ogg", "ogg" },
             { "ogm", "ogg" },
             { "ogv", "ogg" },
+            { "flac","raw" },
             { "mp3", "raw" },
             { "mp4", "mp4" },
             { "mov", "mov" },