[Rails5] Fix test_date_with_string_value test.

Author: metaskills

lib/active_record/connection_adapters/sqlserver/type/date.rb

@@ -10,7 +10,7 @@ def sqlserver_type
 
           def serialize(value)
             return unless value.present?
-            date = value.to_s(:_sqlserver_dateformat)
+            date = super(value).to_s(:_sqlserver_dateformat)
             Data.new date, self
           end