Add mistral back to murano job definitions file
Add mistral back to murano job definitions file

In patch https://review.openstack.org/#/c/225960/1 was a mistake.
This patch adds mistral and its client to PROJECTS variable for
gate-murano-congress-dsvm.

Change-Id: I82d52c20502fc0962028c9ba3413d764de1cff36

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