User server clock in session.ls (#973)
User server clock in session.ls (#973)

Avoids negative time deltas in the case of clock skew between ESX/VC and the client host.
vmware/govmomi,vmware/govmomi,bruceadowns/govmomi,bruceadowns/govmomi,dougm/govmomi,dougm/govmomi,dougm/govmomi,vmware/govmomi,bruceadowns/govmomi