[QT] Fix file dialog file name handling for QT4
[QT] Fix file dialog file name handling for QT4

r0x0r/pywebview,shivaprsdv/pywebview,shivaprsdv/pywebview,shivaprsdv/pywebview,shivaprsdv/pywebview,r0x0r/pywebview,r0x0r/pywebview,r0x0r/pywebview,r0x0r/pywebview