Fix warnings when packaging with leveldown.

[tegefaulkes]

Fixes #1264.
Relates to #837

The goal of this PR is to remove warnings when packaging a project that includes the leveldown native module.
This change should;

• Remove warnings when packaging leveldown.
• packaged executable should run without needing to include the leveldown prebuilds directory with the executable.

[CMCDragonkai]

This is pretty quick fix. Can it be merged soon?

[dsturnbull]

Resolvable in local config, e.g. package.json in the thing you're packaging up:

    "patches": {
      "node_modules/leveldown/binding.js": []
    }

This essentially removes the patch specified in dictionary/leveldown.js while we wait for this PR.

[robertsLando]

This can be handeld now using --no-dict option

[CMCDragonkai]

What is the leveldown.js dictionary used for anyway? Why is it there if packaging native leveldown results in a warning? Why not just remove that dictionary entirely for leveldown?

[CMCDragonkai]

@robertsLando Changing to use --no-dict leveldown option did not work in our case. It resulted in: > Error! Not more than one entry file/directory is expected. Nothing else changed.

We're using something like:

        pkg . \
          --targets node${utils.nodeVersion}-linux-${arch} \
          --no-bytecode \
          --public \
          --public-packages "*" \
          --no-dict leveldown \
          --output out

[CMCDragonkai]

It required leveldown.js.