Legally incredibly dubious, particularly since we don't follow it
strictly as policy, and we have git history instead, which does it right.
This is just a waste of time and a cargo cult.

Signed-off-by: Lamont Granquist <lamont@scriptkiddie.org>

Doing something like:

```
node.default["foo"] = []
node.default["foo"] << { "bar" => "baz }
```

Would result in a Hash instead of a VividMash inserted into the
AttrArray, so that:

```
node.default["foo"][0]["bar"] # gives the correct result
node.default["foo"][0][:bar]  # does not work due to the sub-Hash not
                              # converting keys
```

This fixes that behavior, but is likely a breaking change to someone
who expects to ingest hashes with symbol keys and get back out symbol
keys, they will now get converted to strings.  This breaking change
is fully 100% intentional.  This makes the node attribute structure
more consistent and predictable.

Signed-off-by: Lamont Granquist <lamont@scriptkiddie.org>