xwm: fix typo on windows hints
xwm: fix typo on windows hints

was giving a wrong assignment to window->type.

Signed-off-by: Tiago Vignatti <f080760b2054d506aacc8dee97f8804c19fbc3aa@intel.com>

eyolfson/weston,Gnurou/weston,xorgy/weston,mchalupa/weston,Tarnyko/weston-xdg_surface_present,eyolfson/weston,jonnylamb/weston,giucam/weston,giucam/weston,Fantu/compositor-spice,Fantu/compositor-spice,kwm81/weston,xorgy/weston,kwm81/weston,udoprog/weston,Tarnyko/weston-xdg_surface_present,Gnurou/weston,mchalupa/weston,Fantu/compositor-spice,sir-murray/weston,krezovic/weston,krezovic/weston,jonnylamb/weston,udoprog/weston,sir-murray/weston