Add Xen nothing state '------'
Add Xen nothing state '------'

... which means that a domain is in the queue behind other domains
waiting to be scheduled.  The domain is runnable but it is not
currently running.

Signed-off-by: Jose A. Lopes <jabolopes@google.com>
Reviewed-by: Hrvoje Ribicic <be5828fca31f89218048bec4189e30a581aa65da@google.com>

Cherry-picked from 30350df5fc6b0cda9be12189864ebcca89d8a9ea.

Signed-off-by: Hrvoje Ribicic <be5828fca31f89218048bec4189e30a581aa65da@google.com>
Reviewed-by: Helga Velroyen <2d0126b1ec6f9ec5cbec4a7012aa14faeaef10f5@google.com>

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