Revert a change to audio_audiohook_write_list that had no affect.

When I made this change initially, I was under the false impression that the
audiohooks structure remained on the channel after all of the hooks had been
detached.  This is not the case, ast ast_read takes care of removing the
audiohooks structure if the lists are empty.
........

Merged revisions 355622 from http://svn.asterisk.org/svn/asterisk/branches/1.8


git-svn-id: https://origsvn.digium.com/svn/asterisk/branches/10@355623 65c4cc65-6c06-0410-ace0-fbb531ad65f3

main/audiohook.c

@@ -783,10 +783,6 @@ static struct ast_frame *audio_audiohook_write_list(struct ast_channel *chan, st
 	int middle_frame_manipulated = 0;
 	int removed = 0;
 
-	/* Don't translate our frame if we aren't going to bother to use it */
-	if (ast_audiohook_write_list_empty(audiohook_list))
-		return end_frame;
-
 	/* ---Part_1. translate start_frame to SLINEAR if necessary. */
 	if (!(middle_frame = audiohook_list_translate_to_slin(audiohook_list, direction, start_frame))) {
 		return frame;