R1:6f721fb437c1

Tighten form spacing on checkboxes and radios

Summary: Some longer forms get really long here, this seems easier to read.

Test Plan: Check Flags and admining users.

Reviewers: epriestley

Reviewed By: epriestley

CC: Korvin, aran

Differential Revision: https://secure.phabricator.com/D6825