Deleted check for compute nodes for vcenter
Deleted check for compute nodes for vcenter

It is no need to check env for compute nodes for vcenter tests, because
there is a corresponding deployment tag("use_vcenter"). And vcenter env does
not required a compute nodes.

Change-Id: I314751b951a5571790370ea4c13022d056d76497
Closes-bug: #1431285

eayunstack/fuel-ostf,mcloudv/fuel-ostf,eayunstack/fuel-ostf,stackforge/fuel-ostf,mcloudv/fuel-ostf,stackforge/fuel-ostf