In check mode, the security role will fail when tags are used. This
is because the check_mode variable wasn't being set when tags were
provided. This patch ensures that the tasks that check for check mode
and set the subsequent check_mode variable will run every time.
This is a manual backport of Ib6a29ee4c36632cd6d982ce87105f0ddec4a891d
since the master/Newton branch includes some new things for systemd that
doesn't make sense in Mitaka/Liberty.
Closes-bug: 1590086
Change-Id: Ib6a29ee4c36632cd6d982ce87105f0ddec4a891d