So, the problem is due to http://logs.openstack.org/20/243320/3/check/gate-tempest-dsvm-cells/5952387/logs/screen-n-sch.txt.gz#_2015-11-16_04_41_58_981
It seems that since the cells API doesn't know the hosts correctly, using force_hosts is not working for Cells.
So, the problem is due to http:// logs.openstack. org/20/ 243320/ 3/check/ gate-tempest- dsvm-cells/ 5952387/ logs/screen- n-sch.txt. gz#_2015- 11-16_04_ 41_58_981
It seems that since the cells API doesn't know the hosts correctly, using force_hosts is not working for Cells.