Make "Create New Similar Task" inherit priorities

Summary: Request in T1589, seems reasonable to me.

Test Plan: Created a "Wishlist" task, created a "Similar" task, got "Wishlist" default priority.

Reviewers: vrana, btrahan

Reviewed By: vrana

CC: aran

Maniphest Tasks: T1589

Differential Revision: https://secure.phabricator.com/D3155

src/applications/maniphest/controller/ManiphestTaskEditController.php

@@ -287,6 +287,7 @@ final class ManiphestTaskEditController extends ManiphestController {
             $task->setCCPHIDs($template_task->getCCPHIDs());
             $task->setProjectPHIDs($template_task->getProjectPHIDs());
             $task->setOwnerPHID($template_task->getOwnerPHID());
+            $task->setPriority($template_task->getPriority());
 
             if ($aux_fields) {
               $template_task->loadAndAttachAuxiliaryAttributes();