SCVMM - Host children missing in the relationships tree

The relationship tree (aka the accordion view) works fine when a cluster node has been configured in SCVMM. However, when no cluster nodes exist no relationship is created between the hosts and the 'host folder'.  This commit addresses this by setting the ems_children property of the 'host folder' to the clusters when they exist and to the hosts when they don't.

https://bugzilla.redhat.com/show_bug.cgi?id=1141208
Merge pull request #644 from bronaghs/scvmm_acordion_issues

SCVMM - Host children missing in the relationships tree