Make the chart work with helm 2.2 (#170)

Primarily this involved removing the release namespace, which is
controlled by helm.  If you want resources in a namespace you set
--namespace= with helm install, anything else leaves helm unable
to properly manage the resources.

I think the functions namespace won't work either on a delete.

charts/fission/values.yaml

@@ -20,4 +20,4 @@ routerPort: 31314
 
 ## Namespace in which to run fission functions (this is different from
 ## the release namespace)
-fissionFunctionNamespace: fission-function
+functionNamespace: fission-function