Use write connection and transactions in SQL patches
Summary:
Patches often read from slaves (possibly stale data) and use that information to write on master.
It causes problems when applying more patches quickly after each other because data created in previous patch may not be replicated yet.
Test Plan:
$ bin/storage upgrade
Reviewers: epriestley
Reviewed By: epriestley
CC: aran, Korvin
Differential Revision: https://secure.phabricator.com/D4483