sec-policy/selinux-base: Drop old blocker on selinux-base-policy

sec-policy/selinux-base: Drop old blocker on selinux-base-policy

The purpose of selinux-base is to provide the interface files and base module
(but does not necessarily require it to load). Historically, the package was
the full base policy, but since 2012 this was moved to the selinux-base-policy
package.

A blocker was put in place to ensure proper transitioning.

As we no longer have these policies in our repository, remove this old
blocker.

Package-Manager: portage-2.2.28