hide version for bundled plugins because it's meaningless; for everything else support showing version using git (if about[0] is null)

plugins/af_fsckportal/init.php

@@ -4,7 +4,7 @@ class Af_Fsckportal extends Plugin {
 	private $host;
 
 	function about() {
-		return array(1.0,
+		return array(null,
 			"Remove feedsportal spamlinks from article content",
 			"fox");
 	}