vsh: Filter --options
Similarly to the previous commit, once we've presented an
--option for a command to the user it makes no sense to offer it
again. Therefore, we can prune all already specified options. For
instance, after this patch:
virsh # migrate --verbose <TAB><TAB>
will no longer offer --verbose option.
Signed-off-by: Michal Privoznik <mprivozn@redhat.com>