When installing OpenStack via DevStack on XenServer, we need to
some preparation operations in dom0 which will refer the function
in devstack/tools/xen/functions file, but we are planning to move
the whole folder of tools/xen from devstack to os-xenapi, so it
this patch is to moving the dom0 related operation to os-xenapi
repo first.
Change-Id: Ib59d802a7a4eab4ccce0e29d80f29efa4655bc0b
Depends-On: I712ee74ce945859ba5118e09b7d9436ca2686cb7
f15fd26943