Populate last_boot_CPU_flags on VM.start
Populate last_boot_CPU_flags on VM.start

When a VM is started, last_boot_CPU_flags will be populated with the
"vendor" and "features" fields of the host CPU.

Signed-off-by: John Else <37b74501daa612e48fea94f9846ed4ddeb6a8f07@citrix.com>

simonjbeaumont/xcp-rrdd,djs55/xcp-rrdd,koushikcgit/xcp-networkd,djs55/squeezed,koushikcgit/xcp-rrdd,simonjbeaumont/xcp-rrdd,sharady/xcp-networkd,koushikcgit/xcp-networkd,djs55/xcp-rrdd,djs55/xcp-networkd,djs55/xcp-networkd,johnelse/xcp-rrdd,sharady/xcp-networkd,robhoes/squeezed,koushikcgit/xcp-rrdd,johnelse/xcp-rrdd,koushikcgit/xcp-rrdd