ResourceFileMapper: flush write buffer after writing

Call QFile::flush() after writing the data that was fetched from the
item. This fixes files being empty in some situations.

Signed-off-by: Tobias Doerffel <tobias.doerffel@gmail.com>

include/ResourceFileMapper.h

@@ -42,6 +42,7 @@ public:
 		if( m_tempFile && m_tempFile->open() )
 		{
 			m_tempFile->write( m_item->fetchData() );
+			m_tempFile->flush();
 		}
 	}