Minor fix for CelerityManagementMapWorkflow

Summary: phutil_var_export only accepts a single parameter. This bug was introduced in D9926.

Test Plan: Eye-ball it.

Reviewers: epriestley, Blessed Reviewers

Reviewed By: epriestley, Blessed Reviewers

Subscribers: epriestley, Korvin

Differential Revision: https://secure.phabricator.com/D9930