can't disable namespace

[genadyp]

environment: node

I use same namespace across few files.
When I disable namespace in one file

    let namespaces = enabledNamespaces()
    const index = namespaces.indexOf(namespace)
    namespaces[index] = `-${namespace}`
    debug.enable(namespaces.join())

in other other file I see that debug doesn't have this namespace in the list of names, but the namespace still enabled and there is an output.

[Qix-]

Agreed, the behavior surrounding the global namespaces array is bizarre and unintuitive.

[Qix-]

See #425