Add warnings to JIRA auth provider that we only support JIRA 6

Summary: Ref T4289. Make it clear that this provider does not currently work with JIRA 5.

Test Plan: Viewed JIRA provider from `/auth/`, saw warnings.

Reviewers: btrahan, chad

Reviewed By: chad

CC: aran

Maniphest Tasks: T4289

Differential Revision: https://secure.phabricator.com/D7906

src/applications/auth/provider/PhabricatorAuthProviderOAuth1JIRA.php

@@ -11,6 +11,10 @@ public function getProviderName() {
     return pht('JIRA');
   }
 
+  public function getDescriptionForCreate() {
+    return pht('Configure JIRA OAuth. NOTE: Only supports JIRA 6.');
+  }
+
   public function getConfigurationHelp() {
     if ($this->isSetup()) {
       return pht(
@@ -162,6 +166,11 @@ public function extendEditForm(
           "again."));
     }
 
+    $form->appendRemarkupInstructions(
+      pht(
+        'NOTE: This provider **only supports JIRA 6**. It will not work with '.
+        'JIRA 5 or earlier.'));
+
     $is_setup = $this->isSetup();
 
     $e_required = $request->isFormPost() ? null : true;