The 'os-migrations' API accepts 'instance_uuid' and 'migration_type'
query string parameters, not 'server' and 'type'. For the former, as the
name would suggest, the value should be a server UUID, not a name.
In addition, this is a list command and therefore should subclass the
'Lister' base class.
Change-Id: I736f5575156fc04d7ada7783a1865ab3b438396f
Signed-off-by: Stephen Finucane <sfinucan@redhat.com>