health-server: Fixing hypervisor/arity affinity
health-server: Fixing hypervisor/arity affinity

Before this patch the nodes were not taken of different hypervisors.
In fact, we shall compute arity groups by taken nodes from various
hypervisors.

redhat-cip/edeploy,lebauce/edeploy,enovance/edeploy,enovance/edeploy,redhat-cip/edeploy,lebauce/edeploy,redhat-cip/edeploy,enovance/edeploy,lebauce/edeploy,redhat-cip/edeploy,lebauce/edeploy,enovance/edeploy