sysconfig.xencommons.in: Strip and debianize

sysconfig.xencommons.in: Strip and debianize

Strip all options that are for stuff we don't ship, which is 1)
xenstored as stubdom and 2) xenbackendd, which seems to be dead code
anyway. [1]

It seems useful to give the user the option to revert to xenstored
instead of the default oxenstored if they really want.

[1] https://lists.xen.org/archives/html/xen-devel/2015-07/msg04427.html

Signed-off-by: Hans van Kranenburg <hans@knorrie.org>
Acked-by: Ian Jackson <ijackson@chiark.greenend.org.uk>
Gbp-Pq: Name 0045-sysconfig.xencommons.in-Strip-and-debianize.patch