Fix empty titles on pages without application names

Summary: Fixes T3195. Currently, we show `[] Phabricator` on the homepage with unicode glyphs off.

Test Plan:
Viewed home page and application pages with glyphs on and off. Saw:

|              | Unicode | No Unicode     |
|              | ------- | ----------     |
| Home         | Empty   | Empty          |
| ----         |         |                |
| Differential | Gear    | Differential   |
| ----         |         |                |

Reviewers: btrahan, chad

Reviewed By: btrahan

CC: aran

Maniphest Tasks: T3195

Differential Revision: https://secure.phabricator.com/D5932