Removed duplicate lettuce test from course-export.feature

cms/djangoapps/contentstore/features/course-export.feature

@@ -2,14 +2,6 @@
 Feature: Course export
   I want to export my course to a tar.gz file to share with others or check into source control
 
-  Scenario: User is directed to unit with bad XML when export fails
-    Given I am in Studio editing a new unit
-    When I add a "Blank Advanced Problem" "Advanced Problem" component
-    And I edit and enter bad XML
-    And I export the course
-    Then I get an error dialog
-    And I can click to go to the unit with the error
-
  # Disabling due to failure on master. 05/21/2014 TODO: fix
  # Scenario: User is directed to problem with & in it when export fails
  #   Given I am in Studio editing a new unit