cache: drop setup_cache_regions - tg will already have done that and coerced the types correctly

The configuration and type fixing will be invoked from make_base_app, and we
will thus not have to do it:

File "kallithea/config/middleware.py", line 31, in make_app_without_logging
return make_base_app(global_conf, full_stack=full_stack, **app_conf)
File ".../python3.7/site-packages/tg/configuration/app_config.py", line 176, in make_base_app
wrap_app)
File ".../python3.7/site-packages/tg/configurator/application.py", line 112, in _make_app
app = TGApp(conf)
File ".../python3.7/site-packages/tg/wsgiapp.py", line 49, in __init__
app_wrapper = wrapper(self.wrapped_dispatch, self.config)
File ".../python3.7/site-packages/tg/appwrappers/caching.py", line 36, in __init__
self.options = parse_cache_config_options(config)
File ".../python3.7/site-packages/beaker/util.py", line 430, in parse_cache_config_options

This will fix a py3 problem where setup_cache_regions was run *after* beaker
had coerced types, thus introducing string types in the config where beaker
expected the integers it had put there.