sunrpc: Merge xs_create_sock code

After xs_bind is merged it's easy to merge its callers.

Signed-off-by: Pavel Emelyanov <xemul@openvz.org>
Reviewed-by: Chuck Lever <chuck.lever@oracle.com>
[bfields@redhat.com: fix address family initialization]
Signed-off-by: J. Bruce Fields <bfields@redhat.com>