R1:281e9849ed23

Fix display of current file on Macro creation

Summary: This could hit an obscure fatal.

Test Plan:
- Create a macro.
- Upload a file, but don't give it a name.
- Before: fatal.
- After:

{F2569846}

Reviewers: chad, 20after4

Reviewed By: chad

Differential Revision: https://secure.phabricator.com/D17310