Aprhont - Adding cookie-prefix, as config option, and into cookie methods

Summary: Cookie-prefix should fix phabricator instances where x.com and x.y.com have conflicting cookie names

Test Plan: Pushed branch to dev.phab.example.com, logged into phab.example.com and into dev.phab.example.com.

Reviewers: epriestley, #blessed_reviewers

Reviewed By: epriestley

CC: Korvin, epriestley, aran

Differential Revision: https://secure.phabricator.com/D7979

src/aphront/configuration/AphrontDefaultApplicationConfiguration.php

@@ -107,9 +107,12 @@ class AphrontDefaultApplicationConfiguration
 
     $data += $parser->parseQueryString(idx($_SERVER, 'QUERY_STRING', ''));
 
+    $cookie_prefix = PhabricatorEnv::getEnvConfig('phabricator.cookie-prefix');
+
     $request = new AphrontRequest($this->getHost(), $this->getPath());
     $request->setRequestData($data);
     $request->setApplicationConfiguration($this);
+    $request->setCookiePrefix($cookie_prefix);
 
     return $request;
   }