add tests to ensure that privileged field value is propogated to docker-...

@cjellick 
It would be nice if we didn't have to worry about these port fields in each test. Maybe we should create a new request and response json pair that has the bare minimal configuration needed to create a container, so that each test doesn't have to do the port field manipulation. Also, if the deletion of created, id, and status is repeated in each test, we could extract that to a function.

Seems like we can get the post function down to just a few lines if we made these changes.