Merge pull request #339 from dragos-oancea/switch_ivr_async-nullptr

[core] scan-build: Dereference of null pointer (loaded from variable 'result') - switch_ivr_play_and_detect_speech()

src/switch_ivr_async.c

@@ -4624,7 +4624,9 @@ done:
 	if (state.done) {
 		status = SWITCH_STATUS_SUCCESS;
 	}
-	*result = state.result;
+	if (result) {
+		*result = state.result;
+	}
 
 	arg_recursion_check_stop(args);