Remove 'cache_table' from required params

Starting in Django 1.7, the createcachetable command looks for cache
table names in the CACHES settings dictionary, so cache_table is no
longer required, but is still allowed.

web_infrastructure/django_manage.py

@@ -183,7 +183,6 @@ def main():
 
     command_required_param_map = dict(
         loaddata=('fixtures', ),
-        createcachetable=('cache_table', ),
         )
 
     # forces --noinput on every command that needs it