No support for double nested 64 bit guest using VCDriver

64bit instances launched on ESX via the VCDriver will not
support running 64bit guests. There is an option that can
be passed during the vmx creation that will allow for this
to happen. This is very useful if you want to run hypervisors
 (esx, kvm) on top of ESX and then run 64bit VMs on top of
those hypervisors.

Fixes bug 1192256

Change-Id: Id6eb224c97569737cbb41f1b64f61805e1df004e
Revert "No support for double nested 64 bit guest using VCDriver"

This reverts commit b5aa274aee82184b2a938865d714e84067c2e800.
Revert "Revert "No support for double nested 64 bit guest using VCDriver""

This reverts commit 64bd15e6c33b83ba3ae8073ac455ce4e65a42923.
Merge branch 'master' of github.com:hartsock/nova into bp/vmware-driver-refactor