Fix ackcall problem for Zaptel channels

git-svn-id: https://origsvn.digium.com/svn/asterisk/trunk@4417 65c4cc65-6c06-0410-ace0-fbb531ad65f3

channels/chan_agent.c

@@ -353,6 +353,14 @@ static struct ast_frame  *agent_read(struct ast_channel *ast)
 			p->acknowledged = 0;
 		}
 	}
+	if ((!strncmp(p->chan->name,"Zap",3)) && (!p->ackcall) && (!p->acknowledged))
+        {
+
+                p->acknowledged = 1;
+                f = &answer_frame;
+                if (p->chan)
+                        p->chan->_bridge = ast;
+        }
 	if (f && (f->frametype == AST_FRAME_CONTROL) && (f->subclass == AST_CONTROL_ANSWER)) {
 /* TC */
 		if (p->ackcall) {