path is converted to 8-bit encoding using toLocal8Bit in
QTemporaryFileEngine::open. The reverse operation should be used here.
(cherry picked from commit 023976f9dd48a3deb947905d32d5fc0692da7318)
Change-Id: Idb4c1ca3415300367c46a09d68df640e17b7bfdc Reviewed-by: João Abecasis <joao.abecasis@nokia.com>