[cassandra] we can mock the config, no need for datadog.conf
[cassandra] we can mock the config, no need for datadog.conf

[cassandra][test] importing server will already try to read datadog.conf.

[cassandra][test] add missing key to cassandra.

DataDog/integrations-core,darnould/integrations-core,serverdensity/sd-agent-core-plugins,darnould/integrations-core,DataDog/integrations-core,serverdensity/sd-agent-core-plugins,StackVista/sts-agent-integrations-core,itsuugo/integrations-core,varlib1/servermall,darnould/integrations-core,varlib1/servermall,s-maj/integrations-core,serverdensity/sd-agent-core-plugins,DataDog/integrations-core,DataDog/integrations-core,varlib1/servermall,darnould/integrations-core,serverdensity/sd-agent-core-plugins,StackVista/sts-agent-integrations-core,DataDog/integrations-core,s-maj/integrations-core,varlib1/servermall,s-maj/integrations-core,StackVista/sts-agent-integrations-core,s-maj/integrations-core,DataDog/integrations-core,StackVista/sts-agent-integrations-core,varlib1/servermall,serverdensity/sd-agent-core-plugins,DataDog/integrations-core,DataDog/integrations-core,s-maj/integrations-core,StackVista/sts-agent-integrations-core,DataDog/integrations-core,itsuugo/integrations-core,itsuugo/integrations-core,itsuugo/integrations-core,itsuugo/integrations-core,DataDog/integrations-core,darnould/integrations-core