Rename "PhabricatorHash::digest()" to "weakDigest()"

Summary: Ref T12509. This encourages code to move away from HMAC+SHA1 by making the method name more obviously undesirable.

Test Plan: `grep`, browsed around.

Reviewers: chad

Reviewed By: chad

Maniphest Tasks: T12509

Differential Revision: https://secure.phabricator.com/D17632

src/applications/auth/controller/PhabricatorAuthController.php

@@ -194,7 +194,7 @@ abstract class PhabricatorAuthController extends PhabricatorController {
     // hijacking registration sessions.
 
     $actual = $account->getProperty('registrationKey');
-    $expect = PhabricatorHash::digest($registration_key);
+    $expect = PhabricatorHash::weakDigest($registration_key);
     if (!phutil_hashes_are_identical($actual, $expect)) {
       $response = $this->renderError(
         pht(