Cosmetic changes to common_redirect, clientError, serverError

Since these functions exit (or throw exception) after running, there
is no need to have a 'return' statement or similar afterwards.

plugins/Mapstraction/actions/map.php

@@ -63,7 +63,6 @@ class MapAction extends Action
                 $args['page'] = $this->arg['page'];
             }
             common_redirect(common_local_url($this->trimmed('action'), $args), 301);
-            return false;
         }
 
         $this->user = User::getKV('nickname', $nickname);
@@ -71,7 +70,6 @@ class MapAction extends Action
         if (!$this->user) {
             // TRANS: Client error displayed when referring to a non-existing user.
             $this->clientError(_m('No such user.'), 404);
-            return false;
         }
 
         $this->profile = $this->user->getProfile();
@@ -79,7 +77,6 @@ class MapAction extends Action
         if (!$this->profile) {
             // TRANS: Error message displayed when referring to a user without a profile.
             $this->serverError(_m('User has no profile.'));
-            return false;
         }
 
         $page = $this->trimmed('page');