fixed import before types errors

std/php/db/PDO.hx

@@ -31,6 +31,8 @@ import sys.db.Connection;
 import sys.db.ResultSet;
 #end
 
+import php.Lib;
+
 /**
  * PDO::FETCH_COLUMN = 7
  * PDO::FETCH_CLASS = 8
@@ -87,8 +89,6 @@ extern class PDOStatement
 	public function setFetchMode(mode : Int, ?fetch : Dynamic, ?ctorargs : NativeArray) : Bool;
 }
 
-import php.Lib;
-
 private class PDOConnection implements Connection {
 
 	var pdo : PDOClass;