Beautifier: create temporary file in input file dir

It fixes finding .clang-format file for "clang-format -style=file"

Task-number: QTCREATORBUG-12057
Change-Id: Idd02de1535eef30e1a1eaf146ef0f9ac9d54c5fa
Reviewed-by: Orgad Shaneh <orgads@gmail.com>
Reviewed-by: Eike Ziller <eike.ziller@digia.com>