Ecore_win32: do not handle WM_SYSKEY* events.

Ecore_win32: do not handle WM_SYSKEY* events.

Summary:
In case if WM_SYSKEYDOWN or WM_SYSKEYUP events are handled in
DefWindowProc - system doesn't init event for a system shortcuts.
For example any EFL application on Windows couldn't be closed by
Alt+F4 combination.

@fix

Test Plan:
Launch Elemenatry_test app.
           Try to close by Alt+F4 combination.

Reviewers: vtorri, raster

Reviewed By: raster

Subscribers: an.kroitor, bowonryu, cedric, jpeg, #eflete

Differential Revision: https://phab.enlightenment.org/D4477