do this slightly safer so we don't have the mutex locked when we exec the app

src/switch_channel.c

@@ -2760,10 +2760,12 @@ SWITCH_DECLARE(switch_status_t) switch_channel_perform_ring_ready_value(switch_c
 SWITCH_DECLARE(switch_status_t) switch_channel_execute_on(switch_channel_t *channel, const char *variable_prefix)
 {
 	switch_event_header_t *hi;
+	switch_event_t *event;
 	int x = 0;
 
-	if ((hi = switch_channel_variable_first(channel))) {
-		for (; hi; hi = hi->next) {
+	switch_channel_get_variables(channel, &event);
+	
+	for (hi = event->headers; hi; hi = hi->next) {
 		char *var = hi->name;
 		char *val = hi->value;
 		char *app;
@@ -2785,8 +2787,8 @@ SWITCH_DECLARE(switch_status_t) switch_channel_execute_on(switch_channel_t *chan
 			}
 		}
 	}
-		switch_channel_variable_last(channel);
-	}
+	
+	switch_event_destroy(&event);
 
 	return x ? SWITCH_STATUS_SUCCESS : SWITCH_STATUS_FALSE;
 }