On older hubs --force is not supported, so CLI will fail on unknown
parameter. This use force option only if it is explicitly required.
Fixes: https://pagure.io/koji/issue/1388
Using force option will allow 'pre-blocking' of packages which are not
in tag inheritance yet, but could cause a problem if they'll get to
inheritance chain somehow. In such case we don't have an owner for
package and using 'force' allows admin to introduce blocked package with
him as an owner.
Fixes: https://pagure.io/koji/issue/867
