Fix Q_PLUGIN_EXTRA_CONF_PATH for ironic-multitenant job
Fix Q_PLUGIN_EXTRA_CONF_PATH for ironic-multitenant job

There were a breaking change to devstack [0]
This patch fixes config file path for ironic-multitenant job

Reference:
[0] https://review.openstack.org/#/c/307862/

Change-Id: Ife385cf94868c62cd5f0be2d6bbe1dcc8f39db77

dongwenjuan/project-config,Tesora/tesora-project-config,openstack-infra/project-config,Tesora/tesora-project-config,openstack-infra/project-config,dongwenjuan/project-config