headless: fix the output refresh rate
headless: fix the output refresh rate

60 millihertz is a bit low, let's make it 60 Hz as it was supposed to
be.

When the new repaint scheduling algorithm gets implemented, this
fixes 'make check' taking almost 3 minutes instead of the normal 3
seconds, when running with 7 millisecond repaint window.

Signed-off-by: Pekka Paalanen <0f6ae7001e34c37b02fb2c1c2573ddf8f442136a@collabora.co.uk>
Reviewed-by: Daniel Stone <62e7e355d5d8400fa8384448796af0bf6be4ffae@collabora.com>

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