Removed the parameter use in database drivers' _close() and added a default _close() method in CI_DB_driver + some changelog fixes
diff --git a/system/database/DB_driver.php b/system/database/DB_driver.php
index a955f45..a0812d4 100644
--- a/system/database/DB_driver.php
+++ b/system/database/DB_driver.php
@@ -1152,7 +1152,7 @@
 	{
 		if ($this->conn_id)
 		{
-			$this->_close($this->conn_id);
+			$this->_close();
 			$this->conn_id = FALSE;
 		}
 	}
@@ -1160,6 +1160,20 @@
 	// --------------------------------------------------------------------
 
 	/**
+	 * Close DB Connection
+	 *
+	 * This method would be overriden by most of the drivers.
+	 *
+	 * @return	void
+	 */
+	protected function _close()
+	{
+		$this->conn_id = FALSE;
+	}
+
+	// --------------------------------------------------------------------
+
+	/**
 	 * Display an error message
 	 *
 	 * @param	string	the error message
@@ -1401,7 +1415,7 @@
 	 */
 	public function __destruct()
 	{
-		if ($this->conn_id && ! $this->pconnect)
+		if ( ! $this->pconnect)
 		{
 			$this->close();
 		}
@@ -1410,4 +1424,4 @@
 }
 
 /* End of file DB_driver.php */
-/* Location: ./system/database/DB_driver.php */
+/* Location: ./system/database/DB_driver.php */
\ No newline at end of file