CLOUDSTACK-5080: Hypervisor Capabilities table missing entry for Simulator

Signed-off-by: Prasanna Santhanam <tsp@apache.org>
CLOUDSTACK-5124: Adopt GetDomRVersionAnswer to VR upgradability

While VRs upgrade, cloudstack should still be able to work with older
/newer version of the scripts within VRs. To allow this, the simulator
needs to send the version strings for the domr version response or the
VR start is interrupted.

Signed-off-by: Prasanna Santhanam <tsp@apache.org>