conf: forbid negative number in address(like controller, bus, slot...)

conf: forbid negative number in address(like controller, bus, slot...)

https://bugzilla.redhat.com/show_bug.cgi?id=1171582

When we edit a negative controller address number to a device,
some of them will auto generate a controller with invalid index
number. This will make guest disappear after restart libvirtd.
Instead of allowing negative number for controller index, we
should forbid negative number in these place (we did this before,
but after f18c02ec, virStrToLong_ui changed to allow negative
number). Therefore switch to virStrToLong_uip in these places.

Signed-off-by: Luyao Huang <lhuang@redhat.com>
Signed-off-by: Michal Privoznik <mprivozn@redhat.com>