Fix a couple of calendar export daterange issues

Summary:
Ref T11816. In some cases, Calendar would only export a subset of events because the "export" flag was ignored or the "display" parameter applied an improper date range to the query.

- Make sure the `export` flag gets processed, even though it isn't a "real" field on the search engine.
- Clear the "display" parameter to avoid date range windowing coming from the day/month logic.

Test Plan: Exported a "display=month" view, verified future events came with it.

Reviewers: chad

Reviewed By: chad

Maniphest Tasks: T11816

Differential Revision: https://secure.phabricator.com/D16898

src/applications/calendar/controller/PhabricatorCalendarExportICSController.php

···
     $saved->setParameter('rangeEnd', null);
     $saved->setParameter('upcoming', null);
 
+    // The "month" and "day" display modes imply time ranges.
+    $saved->setParameter('display', 'list');
+
     $query = $engine->buildQueryFromSavedQuery($saved);
 
     $events = $query

src/applications/calendar/query/PhabricatorCalendarEventQuery.php

···
     }
 
     $raw_limit = $this->getRawResultLimit();
-
     if (!$raw_limit && !$this->rangeEnd) {
       throw new Exception(
         pht(

src/applications/calendar/query/PhabricatorCalendarEventSearchEngine.php

···
     );
   }
 
+  public function buildQueryFromSavedQuery(PhabricatorSavedQuery $saved) {
+    $query = parent::buildQueryFromSavedQuery($saved);
+
+    // If this is an export query for generating an ".ics" file, don't
+    // build ghost events.
+    if ($saved->getParameter('export')) {
+      $query->setGenerateGhosts(false);
+    }
+
+    return $query;
+  }
+
   protected function buildQueryFromParameters(array $map) {
     $query = $this->newQuery();
     $viewer = $this->requireViewer();
···
       $query->withImportSourcePHIDs($map['importSourcePHIDs']);
     }
 
-    // Generate ghosts (and ignore stub events) if we aren't querying for
-    // specific events or exporting.
-    if (!empty($map['export'])) {
-      // This is a specific mode enabled by event exports.
-      $query
-        ->withIsStub(false);
-    } else if (!$map['ids'] && !$map['phids']) {
+    if (!$map['ids'] && !$map['phids']) {
       $query
         ->withIsStub(false)
         ->setGenerateGhosts(true);