Fixed travis build. Cassandra 3.0.14 was removed from the apache site.
Fixed travis build. Cassandra 3.0.14 was removed from the apache site.

ppbizapps/kairosdb,kairosdb/kairosdb,kairosdb/kairosdb,ppbizapps/kairosdb,ppbizapps/kairosdb,ppbizapps/kairosdb,kairosdb/kairosdb,ppbizapps/kairosdb,kairosdb/kairosdb,kairosdb/kairosdb,kairosdb/kairosdb