Apply a hack to unbreak bin/storage upgrade across the DB config boundary

Summary: This is gross, but fixes an issue where `bin/storage upgrade` tries to access DB config which doesn't exist yet. We need a version of this for `bin/config` anyway. I'll sort this out into a proper sequenced startup process in a followup.

Test Plan: `bin/storage upgrade` no longer fatals when upgrading across the config boundary.

Reviewers: asherkin, codeblock, btrahan, vrana

Reviewed By: codeblock

CC: aran

Differential Revision: https://secure.phabricator.com/D4512

src/infrastructure/env/PhabricatorEnv.php

@@ -152,11 +152,15 @@ final class PhabricatorEnv {
       phutil_load_library($library);
     }
 
-    // NOTE: This must happen after the other sources are pushed, because it
-    // will draw from lower-level config to bootstrap itself.
-    $stack->pushSource(
-      id(new PhabricatorConfigDatabaseSource('default'))
-        ->setName(pht("Database")));
+    try {
+      $stack->pushSource(
+        id(new PhabricatorConfigDatabaseSource('default'))
+          ->setName(pht("Database")));
+    } catch (AphrontQueryException $recoverable) {
+      // If the database is not available, just skip this configuration
+      // source. This happens during `bin/storage upgrade`, `bin/conf` before
+      // schema setup, etc.
+    }
   }
 
   public static function repairConfig($key, $value) {