Apply a hack to unbreak `bin/storage upgrade` across the DB config boundary

Summary: This is gross, but fixes an issue where `bin/storage upgrade` tries to access DB config which doesn't exist yet. We need a version of this for `bin/config` anyway. I'll sort this out into a proper sequenced startup process in a followup.

Test Plan: `bin/storage upgrade` no longer fatals when upgrading across the config boundary.

Reviewers: asherkin, codeblock, btrahan, vrana

Reviewed By: codeblock

CC: aran

Differential Revision: https://secure.phabricator.com/D4512