Pylint 2 fixes

[scop]

Description:

I'm working on upgrading pylint to 2.0.0. It reports quite a few new things (more on that later in a separate PR), but here are some easliy fixable low hanging fruits.

Checklist:

• The code change is tested and works locally.
• Local tests pass with tox. Your PR cannot be merged unless tests pass

If user exposed functionality or configuration variables are added/changed:

• Documentation added/updated in home-assistant.github.io

If the code communicates with devices, web services, or third-party tools:

• New dependencies have been added to the REQUIREMENTS variable (example).
• New dependencies are only imported inside functions that use them (example).
• New or updated dependencies have been added to requirements_all.txt by running script/gen_requirements_all.py.
• New files were added to .coveragerc.

If the code does not interact with devices:

• Tests have been added to verify that the new code works.

[balloob]

Is this needed?

From PyLint changelog:

Don't emit unused-import anymore for typing imports used in type comments.

[scop]

Yes, it's still needed. Note used in type comments in the pylint changelog -- in this case, Optional, Dict, and Any are not used anywhere. (In my opinion, these cases should be fixed for real by just dropping the actually unused imports, but that's slightly off topic for this particular PR.)

[balloob]

I think that dropping the unused ones should be appropriate. What's the use of importing something and not using it? Isn't that exactly what PyLint is checking?

[scop]

I suppose it's just an oversight in many places. I'll modify this PR to drop the import-error changes and will take a look at addressing them in a separate one.

[scop]

I've pushed a "Revert pylint 2 inline disable syntax fixes addressing unused-imports" commit to the source branch, but it seems github is having issues at the moment and that commit doesn't show up here yet. Not sure if I should do something about it, but will wait at least a bit first.