There are heat, cinder, neutron, glance, nova and keystone actions
in Mistral. We can call any of them in workflows, but in case of
absence of one of the called services, we will get "list index out
of range" error. This patch fixes the issue.
Closes-Bug: #1422725
Change-Id: I05acb5a27eb82c08b712f9687fc8230b2275ed44