Genericize test cases and namespace create pod

This change modifies 020_check-create-pod and 030_check-network test cases to
target `kube-master[0]` instead of `node1` as these tests can be useful in
deployments that do not use the same naming convention as the basic tests.

This change also modifies 020_check-create-pod to namespace into a `test`
namespace allowing the `get pods` command to get its expected number of
running containers.

Closes #866 and #867.

tests/testcases/030_check-network.yml

@@ -1,5 +1,5 @@
 ---
-- hosts: node1
+- hosts: kube-master[0]
 
   tasks: