Forward-port: patch 3/4 extended HVM features for 1.2
Forward-port: patch 3/4 extended HVM features for 1.2

This patch adds hypervisor support for the extended HVM features.

Author: schreiberal
Reviewed-by: iustinp


onponomarev/ganeti,mbakke/ganeti,yiannist/ganeti,ganeti/ganeti,apyrgio/snf-ganeti,apyrgio/snf-ganeti,bitemyapp/ganeti,apyrgio/ganeti,leshchevds/ganeti,ganeti-github-testing/ganeti-test-1,leshchevds/ganeti,bitemyapp/ganeti,ganeti/ganeti,apyrgio/ganeti,ganeti-github-testing/ganeti-test-1,onponomarev/ganeti,dimara/ganeti,grnet/snf-ganeti,ganeti/ganeti,grnet/snf-ganeti,andir/ganeti,andir/ganeti,mbakke/ganeti,mbakke/ganeti,yiannist/ganeti,andir/ganeti,dimara/ganeti,leshchevds/ganeti,yiannist/ganeti