fix the filtered query string so it can potentially be re-used as is.

(cherry picked from commit 6adbb93f0a)

boot.php

@@ -878,6 +878,8 @@ class App {
 			// removing trailing / - maybe a nginx problem
 			if (substr(self::$query_string, 0, 1) == "/")
 				self::$query_string = substr(self::$query_string, 1);
+			// change the first & to ? 
+			self::$query_string = preg_replace('/&/','?',self::$query_string,1);
 		}
 
 		if(x($_GET,'q'))