Fix bin/accountadmin when not making changes

Summary: If you go through the accountadmin flow and change nothing, you get an exception about the transaction not having any effect. Instead, let the applyTransactions call continue even on no effect.

Test Plan: Ran accountadmin without changing anything for an existing user. No longer got an exception about no-effect transactions.

Reviewers: epriestley

Reviewed By: epriestley

Subscribers: Korvin

Differential Revision: https://secure.phabricator.com/D20009