Various linter fixes

Summary:
Fixed various linter issues that were identified by running arc lint --everything.

• Removed trailing whitespace.
• Added newline at EOF.
• Added whitespace after if statement

Test Plan: N/A

Reviewers: epriestley, Blessed Reviewers

Reviewed By: epriestley

CC: aurelijus, Korvin, epriestley, aran

Differential Revision: https://secure.phabricator.com/D8337