backport: 133e3e38f0c2b14421b4a1e29825f00ec99027ef
backport: 133e3e38f0c2b14421b4a1e29825f00ec99027ef

ecore/wayland: Sync before assuming that there's no output.

This will make the mainloop block waiting for the output info, if it's
not there yet, but it's better than just returning with no screen size.

gfriloux/ecore,gfriloux/ecore,gfriloux/ecore