Fix typo in Hooked.js

[Kyrrui]

Working on a project that was getting an error from cache being undefined, realized in stateManager cache is initialized as such
"self._cache = new Cache(self._trie);" with a preceding underscore.

[holgerd77]

Hi Kyle @Kyrrui, thanks for reporting this! The StateManager has been reworked in the v2.5.0 release and we are now on the path towards a stable external StateManger API.

I haven't thought about this hooked.js part along with this (and I haven't been in contact with the code yet), but as far as I read from the comment on top this file should probably also marked as DEPRECATED and removed in a v3.0.0 release, @mattdean-digicatapult do you have a stance on this?

So as an in between note for you (@Kyrrui) and others using hooked.js: you should probably have some look into the StateManager API once time permits and see if you can update your code to factor out the hooked.js usage and use StateManager directly. It would be very valuable feedback if you tell us about your experiences and how well this worked out (or not).

As a short-term path I would suggest that we merge the PR here and do a minor release, so that people currently using hooked.js are not left behind, together with the DEPRECATION note. Than current users get some more time to get their code ready.

Does this make sense?

[Kyrrui]

@holgerd77 Sounds good to me - although we are not using your library directly, instead we are using Metamask's web3-provider-engine which calls fromWeb3Provider in hooked.js
https://github.com/MetaMask/provider-engine/blob/abd9663419034be70fce8da9f0fbdd6e736b7c1d/subproviders/vm.js#L116
So would have to reach out to them to deprecate or update code.

CC @kumavis

[mattdean-digicatapult]

I think that makes sense @holgerd77. hooked.js should be deprecated and a second stateManager implementation created that exposes the required features.

One question though is should we just deprecate it here and an external project can implement the new stateManager impl or should ethereumjs-vm be providing this functionality?

[holgerd77]

This was re-submitted here #434, have merged the new PR since the one here is out-of-date with the base branch, will close.