Only tries to guess web server user if none provided with 'group' parameter

Mage/Task/BuiltIn/Filesystem/PermissionsReadableOnlyByWebServerTask.php

@@ -29,7 +29,7 @@ class PermissionsReadableOnlyByWebServerTask extends PermissionsTask
     {
         parent::init();
 
-        $this->setGroup($this->getParameter('group', $this->getWebServerUser()))
+        $this->setGroup($this->getParameter('group') ? $this->getParameter('group') : $this->getWebServerUser())
              ->setRights('040');
     }
 

Mage/Task/BuiltIn/Filesystem/PermissionsTask.php

@@ -27,7 +27,8 @@ use Mage\Task\SkipException;
 class PermissionsTask extends AbstractTask
 {
     /**
-     * Paths to change of permissions separated by PATH_SEPARATOR.
+     * Paths to change of permissions in an array or a string separated by
+     * PATH_SEPARATOR.
      *
      * If the stage is on local host you should give full paths. If on remote
      * you may give full or relative to the current release directory paths.

Mage/Task/BuiltIn/Filesystem/PermissionsWritableByWebServerTask.php

@@ -29,7 +29,7 @@ class PermissionsWritableByWebServerTask extends PermissionsTask
     {
         parent::init();
 
-        $this->setGroup($this->getParameter('group', $this->getWebServerUser()))
+        $this->setGroup($this->getParameter('group') ? $this->getParameter('group') : $this->getWebServerUser())
              ->setRights('g+w');
     }