If cogl fails to open the drm device, initialize gbm, or open the
egl display, then it closes the drm fd, uninitializes gbm, closes the
display and then calls _cogl_winsys_renderer_disconnect which does
most of those things again, on the, now deinitialized, members.
This commit removes the explicit failure handling in renderer_connect and
defers cleanup to disconnect.
https://bugzilla.gnome.org/show_bug.cgi?id=754540