Add test to api/cluster_test to make sure a cluster is not updated if a pool does not exist
Add test to api/cluster_test to make sure a cluster is not updated if a pool does not exist

ArxdSilva/tsuru,tsuru/tsuru,ggarnier/tsuru,guilhermebr/tsuru,tsuru/tsuru,ArxdSilva/tsuru,ggarnier/tsuru,guilhermebr/tsuru,tsuru/tsuru,tsuru/tsuru,guilhermebr/tsuru,guilhermebr/tsuru,ArxdSilva/tsuru,ggarnier/tsuru,ggarnier/tsuru,ArxdSilva/tsuru