Use a variable for which conf file to write to
Use a variable for which conf file to write to

In preperation for writing heat_integrationtests config to
tempest.conf instead.

blueprint tempest-plugin-support

Change-Id: I9aa75b0a0052754ede32752a6add93827283a0df

noironetworks/heat,cwolferh/heat-scratch,cwolferh/heat-scratch,openstack/heat,openstack/heat,noironetworks/heat