crosvm: allow specifying wayland path and group
crosvm: allow specifying wayland path and group

Add a wayland-sock argument for specifying the path to the
wayland socket. Also add a wayland-group argument for specifying
the group that has access to that socket.

BUG=none
TEST=crosvm starts with wayland

Change-Id: I3e53eb697951200340613663dc3e4ed28d8ed7f8
Reviewed-on: https://chromium-review.googlesource.com/733732
Commit-Ready: Stephen Barber <7719587e4b5a49340661b214ec85602f3918d06f@chromium.org>
Tested-by: Stephen Barber <7719587e4b5a49340661b214ec85602f3918d06f@chromium.org>
Reviewed-by: Dylan Reid <c791bfe44996c1eed9c7149a0c5f12a86d58eb85@chromium.org>

google/crosvm,google/crosvm,google/crosvm,google/crosvm