installer: remove configure_mmopenshift_selinux_policy

At this point, it's dead code as selinux-policy is updated.

Bug 1173288 - remove configure_mmopenshift_selinux_policy
https://bugzilla.redhat.com/show_bug.cgi?id=1173288
Merge pull request #510 from sosiouxme/2.2-bz1173288-rm-mmopenshift_sepol

installer: remove configure_mmopenshift_selinux_policy