Travis [CI] Is Not Happy - Code Style Errors

As a recent new contributor to LBRY (.tech in particular), I was saddened to see, as part of the process for pull requests (#312 for example), that [Travis CI failed the build](https://travis-ci.org/lbryio/lbry.tech/builds/646680888?utm_source=github_status&utm_medium=notification).

I am currently in the software engineering field, more specifically devops-y releated, and seing a failed build makes me sad. So, while it is a little difficult to describe the Expected and Actual Behaviors, I did notice a few entries that appear to be correctable code style errors (without digging into the source right away before creating this issue):

- no-multi-spaces
- prefer-const
- no-useless-return
- arrow-spacing

As someone not quite versed in JavaScript, I am not sure I would be sufficient in resolving the few prefer-promise-reject-errors entries, so I am thinking of just tackling the "simple"-looking errors for now, in hopes to at least reduce the errors reported. I don't know if the 25 style errors are the maximum the linter/checker will report - maybe there are additional ones after fixing the ones already reported?

I don't think it would hurt [too much] to at least get started in tackling the bugs, to get Travis to a happy/happier state.

Start with the linked Travis CI build and review the reported JavaScript style errors: no-multi-spaces, prefer-const, no-useless-return, arrow-spacing, and prefer-promise-reject-errors. Done means correcting the applicable errors and confirming that the Travis CI build reports a happy or improved result.

Written by the indexing model from the issue text.