compositor: add safety check when EGL fails to initialize

offending message:

    Program received signal SIGSEGV, Segmentation fault.
    create_pointer_images (ec=0x619f10) at compositor.c:240
    240         glEGLImageTargetTexture2DOES(GL_TEXTURE_2D,

Signed-off-by: Tiago Vignatti <tiago.vignatti@nokia.com>

compositor/compositor-x11.c

@@ -659,7 +659,8 @@ x11_compositor_create(struct wl_display *display, int width, int height)
 	x11_compositor_get_resources(c);
 
 	c->base.wl_display = display;
-	x11_compositor_init_egl(c);
+	if (x11_compositor_init_egl(c) < 0)
+        return NULL;
 
 	/* Can't init base class until we have a current egl context */
 	if (wlsc_compositor_init(&c->base, display) < 0)