xwayland: Remove unneeded variable

Just a small code cleanup, there is no need to allocate a variable only
to check the return value of eglInitialize().

Signed-off-by: Olivier Fourdan <ofourdan@redhat.com>
Reviewed-by: Michel Dänzer <mdaenzer@redhat.com>
Reviewed-by: Tony Lindgren <tony@atomide.com>
4 jobs for refactor-glamor-init in 4 minutes and 28 seconds (queued for 2 seconds)