Use EnsureDirs in KVM as well.
Use EnsureDirs in KVM as well.

The KVM hypervisor has also code to ensure a list of directories exist.
Substitute it with our new utils function.

Reviewed-by: iustinp


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