bin/storage shell: force TCP

Summary:
mysql has the magic feature of ignoring port arguments and using the socket when connecting to localhost.

This flag makes it not do that.

Test Plan: ./bin/storage shell, execute status, see Connection: localhost via TCP/IP.

Reviewers: joshuaspence, #blessed_reviewers, epriestley

Reviewed By: #blessed_reviewers, epriestley

Subscribers: Korvin

Differential Revision: https://secure.phabricator.com/D16317