SqlsrvResult: fixed illegal false return value from sqlsrv_fetch_arra…

…y() (#344)

On error, sqlsrv_fetch_array() returns false, which causes an error due to the return type declaration. This commit handles that by casting such value to null the same way other result drivers do it.

src/Dibi/Drivers/SqlsrvResult.php

@@ -61,7 +61,7 @@ public function getRowCount(): int
 	 */
 	public function fetch(bool $assoc): ?array
 	{
-		return sqlsrv_fetch_array($this->resultSet, $assoc ? SQLSRV_FETCH_ASSOC : SQLSRV_FETCH_NUMERIC);
+		return Dibi\Helpers::false2Null(sqlsrv_fetch_array($this->resultSet, $assoc ? SQLSRV_FETCH_ASSOC : SQLSRV_FETCH_NUMERIC));
 	}