R1:209861500f52

Use "en_US.UTF-8", not "C", as the LANG setting

Summary: `LANG=C` is smooshing UTF-8 in some cases. See IRC.

Test Plan: User confirmed this works.

Reviewers: btrahan, asherkin

Reviewed By: asherkin

CC: aran

Differential Revision: https://secure.phabricator.com/D7659