R1:b0495ad9aff9

in test environments, install beta applications

Summary:
Following on from D5938, also need to override the beta setting
so that testApplicationsInstalled passes

Test Plan: testApplicationsInstalled passes

Reviewers: epriestley, nh

Reviewed By: epriestley

CC: aran, Korvin

Differential Revision: https://secure.phabricator.com/D6001