Downgrade from 2.10 to 2.9 correctly
Downgrade from 2.10 to 2.9 correctly

Add handling for Open vSwitch related configuration parameters as well
as for the "cpuid" and "soundhw" hypervisor parameters.

Signed-off-by: Thomas Thrainer <98bdeac947eb8ca18146e9ce7f092788ec242cd1@google.com>
Reviewed-by: Jose A. Lopes <0fb9c4f8511df4ec2ae28af879e9d462f6218a2c@google.com>

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