Fixed #984 - str_replace null parameters deprecated (#989)

Author: huseyinaslim

MysqliDb.php

@@ -551,7 +551,7 @@ private function queryUnprepared($query)
      * @return string Contains the returned rows from the query.
      */
     public function rawAddPrefix($query){
-        $query = str_replace(PHP_EOL, null, $query);
+        $query = str_replace(PHP_EOL, '', $query);
         $query = preg_replace('/\s+/', ' ', $query);
         preg_match_all("/(from|into|update|join) [\\'\\´]?([a-zA-Z0-9_-]+)[\\'\\´]?/i", $query, $matches);
         list($from_table, $from, $table) = $matches;