tools/xenstore: remove socket-only option from xenstore client

tools/xenstore: remove socket-only option from xenstore client

The Xenstore access commands (xenstore-*) have the possibility to limit
connection to Xenstore to a local socket (option "-s"). This is an
option making no sense at all, as either there is only a socket, so
the option would be a nop, or there is no socket at all (in case
Xenstore is running in a stubdom or the client is called in a domU),
so specifying the option would just lead to failure.

So drop that option completely.

Signed-off-by: Juergen Gross <jgross@suse.com>
Acked-by: Wei Liu <wl@xen.org>