Don't crash when pause/stop keys aren't defined on the command line (Bug #3514)

git-svn-id: https://origsvn.digium.com/svn/asterisk/trunk@4970 65c4cc65-6c06-0410-ace0-fbb531ad65f3

file.c

@@ -995,6 +995,14 @@ char ast_waitstream_fr(struct ast_channel *c, const char *breakon, const char *f
 {
 	int res;
 	struct ast_frame *fr;
+
+	if (!breakon)
+			breakon = "";
+	if (!forward)
+			forward = "";
+	if (!rewind)
+			rewind = "";
+	
 	while(c->stream) {
 		res = ast_sched_wait(c->sched);
 		if ((res < 0) && !c->timingfunc) {
@@ -1059,6 +1067,9 @@ char ast_waitstream_full(struct ast_channel *c, const char *breakon, int audiofd
 	int outfd;
 	struct ast_frame *fr;
 	struct ast_channel *rchan;
+
+	if (!breakon)
+		breakon = "";
 	
 	while(c->stream) {
 		ms = ast_sched_wait(c->sched);