Declare variables for freeipa_setup.sh script
Declare variables for freeipa_setup.sh script

These were assumed to be always passed, but as the script gets
different cases (novajoin vs pre-defined service principals) we might
get "unbound variable" errors when used outside of CI. Exporting these
variables beforehand prevents that.

Change-Id: I195321354df167c09cfc87c5b9f86c6dc5026d75

dprince/tripleo-heat-templates,openstack/tripleo-heat-templates,dprince/tripleo-heat-templates,openstack/tripleo-heat-templates