protobuf: Fix show of nested messages in pretty format

Currently the pretty format leaks to the nested messages and
affects the way they are shown. Fix this by assuming the nested
messages to be non-pretty.
Signed-off-by: Pavel Emelyanov <xemul@parallels.com>

protobuf.c

@@ -341,7 +341,7 @@ static int pb_field_show_pretty(pb_pr_ctl_t *ctl)
 	char cookie[32];
 	const char *ptr;
 
-	if (!ctl->pretty_fmt)
+	if (!ctl->pretty_fmt || field->depth)
 		return 0;
 
 	sprintf(cookie, " %d:", field->number);