fixes #7388 - run foreman-selinux-enable on upgrade to reload policy

Works with https://github.com/theforeman/foreman-selinux/pull/33, merge this first though.

Scratch builds:
http://koji.katello.org/koji/taskinfo?taskID=161561 el6
http://koji.katello.org/koji/taskinfo?taskID=161562 el7
http://koji.katello.org/koji/taskinfo?taskID=161563 f19

Bonus scratch builds with a higher nevra, in case you want to test upgrades from the above:
http://koji.katello.org/koji/taskinfo?taskID=161566 el6
http://koji.katello.org/koji/taskinfo?taskID=161568 el7
http://koji.katello.org/koji/taskinfo?taskID=161570 f19

I'd recommend testing upgrades from 1.6.0 to these builds.

---

<pre>
# rpm -e foreman-selinux --nodeps
# rpm -ivh "http://yum.theforeman.org/releases/1.6/el7/x86_64/foreman-selinux-1.6.0-1.el7.noarch.rpm"
Retrieving http://yum.theforeman.org/releases/1.6/el7/x86_64/foreman-selinux-1.6.0-1.el7.noarch.rpm
warning: /var/tmp/rpm-tmp.oJAjV5: Header V4 RSA/SHA1 Signature, key ID 667d1f07: NOKEY
Preparing...                          ################################# [100%]
Updating / installing...
   1:foreman-selinux-1.6.0-1.el7      ################################# [100%]
# semodule -l | grep foreman
foreman	1.6.0.1	
# rpm -Uvh "http://koji.katello.org/koji/getfile?taskID=161565&name=foreman-selinux-1.7.0-0.develop.git.0.1ef598b.git.0.1ef598b.el7.noarch.rpm"
Retrieving http://koji.katello.org/koji/getfile?taskID=161565&name=foreman-selinux-1.7.0-0.develop.git.0.1ef598b.git.0.1ef598b.el7.noarch.rpm
Preparing...                          ################################# [100%]
Updating / installing...
   1:foreman-selinux-1.7.0-0.develop.g################################# [ 50%]
Cleaning up / removing...
   2:foreman-selinux-1.6.0-1.el7      ################################# [100%]
# semodule -l | grep foreman
foreman	1.7.0.0.0.0	
# rpm -Uvh "http://koji.katello.org/koji/getfile?taskID=161571&name=foreman-selinux-1.7.0-1.develop.git.0.3e04ba0.git.0.3e04ba0.el7.noarch.rpm"
Retrieving http://koji.katello.org/koji/getfile?taskID=161571&name=foreman-selinux-1.7.0-1.develop.git.0.3e04ba0.git.0.3e04ba0.el7.noarch.rpm
Preparing...                          ################################# [100%]
Updating / installing...
   1:foreman-selinux-1.7.0-1.develop.g################################# [ 50%]
Cleaning up / removing...
   2:foreman-selinux-1.7.0-0.develop.g################################# [100%]
# semodule -l | grep foreman
foreman	1.7.0.1.0.0
# foreman-selinux-enable; echo $?
0
# semodule -l | grep foreman
foreman	1.7.0.1.0.0	
</pre>