Correct mistral-executor image name
Correct mistral-executor image name

TrivialFix

Change-Id: I24838b3487baa97d8a03bbde2ecdfb42c29ebb80

openstack/kolla,stackforge/kolla,intel-onp/kolla,mandre/kolla,intel-onp/kolla,coolsvap/kolla,mandre/kolla,mandre/kolla,stackforge/kolla,nihilifer/kolla,coolsvap/kolla,stackforge/kolla,dardelean/kolla-ansible,openstack/kolla,rahulunair/kolla,dardelean/kolla-ansible,GalenMa/kolla,mrangana/kolla,dardelean/kolla-ansible,coolsvap/kolla,mrangana/kolla,nihilifer/kolla,GalenMa/kolla,rahulunair/kolla