libei: skip logging if we don't have a log handler

Mostly useful for the unit tests, saves on setup.

Signed-off-by: Peter Hutterer <peter.hutterer@who-t.net>

src/libei-log.c

@@ -127,7 +127,7 @@ ei_log_msg_va(struct ei *ei,
 	      const char *format,
 	      va_list ap)
 {
-	if (ei->log.priority > priority)
+	if (ei->log.priority > priority || !ei->log.handler)
 		return;
 
 	char line[1024];