Remove unused Conpherence sprites

Summary: These were refactored out a while ago

Test Plan: Grep codebase, use Conpherence on desktop, mobile.

Reviewers: btrahan, epriestley

Reviewed By: epriestley

Subscribers: Korvin, epriestley

Differential Revision: https://secure.phabricator.com/D11023

scripts/celerity/generate_sprites.php

@@ -29,7 +29,6 @@ $generator = new CeleritySpriteGenerator();
 $sheets = array(
   'menu' => $generator->buildMenuSheet(),
   'apps' => $generator->buildAppsSheet(),
-  'conpherence' => $generator->buildConpherenceSheet(),
   'apps-large' => $generator->buildAppsLargeSheet(),
   'payments' => $generator->buildPaymentsSheet(),
   'tokens' => $generator->buildTokenSheet(),