Set flag in Tempest enabling Ironic scenario tests

When Ironic has been configured as the backing compute driver,
set the corresponding flag in Tempest that will cause a corresponding
scenario test to run.

Change-Id: I2bb6009c338cb301bd332e640a845fc1f6cb9336
euca-bundle-image requires a new architecture parameter

Ran into this issue while trying to enable UCA. This switch was
documented by the euca2ools team in:
https://eucalyptus.atlassian.net/browse/DOC-807

Closes-Bug: #1304571

Change-Id: I1ea7c6a760c75e67f09e566d73e571be3a1d89ea
Merge "euca-bundle-image requires a new architecture parameter"
Merge "Set flag in Tempest enabling Ironic scenario tests"
Merge commit 'refs/changes/83/86083/1' of git://gold.eng.hq.xensource.com/git/github/openstack-dev/devstack into tmpbranch