Merged revisions 288005 via svnmerge from

https://origsvn.digium.com/svn/asterisk/branches/1.4

........
  r288005 | bbryant | 2010-09-21 15:43:46 -0400 (Tue, 21 Sep 2010) | 8 lines
  
  Add a check to fix a rare segmentation fault you'd get if ast_frdup couldn't allocate
  memory on the first frame being queued in ast_queue_frame.
  
  (closes issue #17882)
  Reported by: seanbright
  Tested by: seanbright
........


git-svn-id: https://origsvn.digium.com/svn/asterisk/branches/1.6.2@288006 65c4cc65-6c06-0410-ace0-fbb531ad65f3

main/channel.c

@@ -1019,7 +1019,9 @@ static int __ast_queue_frame(struct ast_channel *chan, struct ast_frame *fin, in
 	AST_LIST_HEAD_INIT_NOLOCK(&frames);
 	for (cur = fin; cur; cur = AST_LIST_NEXT(cur, frame_list)) {
 		if (!(f = ast_frdup(cur))) {
-			ast_frfree(AST_LIST_FIRST(&frames));
+			if (AST_LIST_FIRST(&frames)) {
+				ast_frfree(AST_LIST_FIRST(&frames));
+			}
 			ast_channel_unlock(chan);
 			return -1;
 		}