Remove test invalidated by better content-type detection semantics

test/io_adapters/file_adapter_test.rb

@@ -69,17 +69,6 @@ class FileAdapterTest < Test::Unit::TestCase
         end
       end
 
-      context "file with multiple possible x-types but no official type" do
-        setup do
-          MIME::Types.stubs(:type_for).returns([MIME::Type.new('image/x-mp4'), MIME::Type.new('image/x-video')])
-          @subject = Paperclip.io_adapters.for(@file)
-        end
-
-        should "return the first" do
-          assert_equal "image/x-mp4", @subject.content_type
-        end
-      end
-
       context "file with content type derived from file command on *nix" do
         setup do
           MIME::Types.stubs(:type_for).returns([])