e2e: do not run date range test

Date Range test sometimes fails (seen on Windows QA box in FF 32).

We will track that in issue #559.

Mark as broken so that it does not trip up customers -- the app is
verified to be working as designed.

Author: laurelnaiad

specs/features/as-joe/explore-docs-by-date-range.feature

@@ -4,6 +4,7 @@ Feature: Explore Docs By Date Range
   When searching for documents, a facet filter may be applied to limit results to
   those documents which created by the user.
 
+  @broken @559
   Scenario: As a contributor filtering by date range, I see the correct results
     Given I am "Joe"
     When I visit the "explore" page