Verify vdsm cluster level support before send getHardwareInfo request

Without verifying vdsm cluster support level the engine sends API
request that does not exist in vdsm. This raises exception in engine.

This path adds verification for vdsm cluster support.

Change-Id: I240786444bdf393f6df4e53daf94d0ee197ecb73
Bug-Id: https://bugzilla.redhat.com/show_bug.cgi?id=894317
Signed-off-by: Yaniv Bronhaim <ybronhei@redhat.com>