Can't select new namespace when current namespace is deleted

[drigz]

If I'm viewing a namespace with kubebox, but the namespace is deleted, I'm no longer able to select a new namespace until I quit and restart kubebox.

Repro:

1. kubectl create namespace foo
2. kubebox then select namespace foo and press Enter
3. kubectl delete namespace foo
4. In kubebox, press n and try to select a different namespace

Expected behavior: can select a new, non-deleted namespace.

Observed behavior: namespace dialog doesn't work, no namespace is highlighted, can't use up/down to select a namespace.

[drigz]

@ensonic FYI