Made declaration of ReleephRequestDifferentialCreateController::willProcessRequest() consistent with AphrontController::willProcessRequest(array $uri_data)

Summary:
When submitting a diff I noticed that the unit test `testEverythingImplemented` threw an error that did not fail a test.

```
[2013-03-18 16:35:16] ERROR 2048: Declaration of ReleephRequestDifferentialCreateController::willProcessRequest() should be compatible with AphrontController::willProcessRequest(array $uri_data) at [/home/anhnhan/dev/vanilla/phabricator/src/applications/releeph/controller/request/ReleephRequestDifferentialCreateController.php:99]
  #0 PhutilBootloader::executeInclude called at [/home/anhnhan/dev/vanilla/libphutil/src/__phutil_library_init__.php:203]
  #1 PhutilBootloader::executeInclude(/home/anhnhan/dev/vanilla/phabricator/src/applications/releeph/controller/request/ReleephRequestDifferentialCreateController.php) called at [/home/anhnhan/dev/vanilla/libphutil/src/__phutil_library_init__.php:193]
  #2 PhutilBootloader::loadLibrarySource(phabricator, applications/releeph/controller/request/ReleephRequestDifferentialCreateController.php) called at [/home/anhnhan/dev/vanilla/libphutil/src/symbols/PhutilSymbolLoader.php:341]
  #3 PhutilSymbolLoader::loadSymbol(Array of size 4 starting with: { type => class }) called at [/home/anhnhan/dev/vanilla/libphutil/src/symbols/PhutilSymbolLoader.php:246]
  #4 PhutilSymbolLoader::selectAndLoadSymbols() called at [/home/anhnhan/dev/vanilla/phabricator/src/infrastructure/__tests__/PhabricatorInfrastructureTestCase.php:15]
  #5 PhabricatorInfrastructureTestCase::testEverythingImplemented()
  #6 call_user_func_array(Array of size 2 starting with: { 0 => Object PhabricatorInfrastructureTestCase }, Array ) called at [/home/anhnhan/dev/vanilla/arcanist/src/unit/engine/phutil/ArcanistPhutilTestCase.php:441]
  #7 ArcanistPhutilTestCase::run() called at [/home/anhnhan/dev/vanilla/arcanist/src/unit/engine/PhutilUnitTestEngine.php:60]
  #8 PhutilUnitTestEngine::run() called at [/home/anhnhan/dev/vanilla/arcanist/src/workflow/ArcanistUnitWorkflow.php:160]
  #9 ArcanistUnitWorkflow::run() called at [/home/anhnhan/dev/vanilla/arcanist/scripts/arcanist.php:271]
```

Test Plan:
`arc unit --everything` before this change gave error.

applied this change. Re-ran `arc unit --everything`, no error.

Reviewers: edward

Reviewed By: edward

CC: aran, epriestley

Differential Revision: https://secure.phabricator.com/D5373