Normalize project slugs before querying for them

Summary:
Fixes T5728. In particular:

  - `/tag/XYZ/` now works as an alias for `/tag/xyz/`.
  - `arc todo --project ASDF` now works as an alias for `arc todo --project asdf`.

Test Plan: Called `project.query` and visited `/tag/LBHABLHBH/`.

Reviewers: btrahan

Reviewed By: btrahan

Subscribers: aklapper, epriestley

Maniphest Tasks: T5728

Differential Revision: https://secure.phabricator.com/D10144

src/applications/project/query/PhabricatorProjectQuery.php

@@ -266,10 +266,15 @@ final class PhabricatorProjectQuery
     }
 
     if ($this->slugs) {
+      $slugs = array();
+      foreach ($this->slugs as $slug) {
+        $slugs[] = rtrim(PhabricatorSlug::normalize($slug), '/');
+      }
+
       $where[] = qsprintf(
         $conn_r,
         'slug.slug IN (%Ls)',
-        $this->slugs);
+        $slugs);
     }
 
     if ($this->phrictionSlugs) {