config: change default .ini to always include trace_errors settings and thus avoid deprecation warnings

Gets rid of:

data/env/lib/python2.7/site-packages/tg/configuration/app_config.py:473
data/env/lib/python2.7/site-packages/tg/configuration/app_config.py:473: DeprecationWarning: direct usage of error tracing options has been deprecated, please specify them as trace_errors.option_name instad of directly setting option_name. EXAMPLE: trace_errors.error_email
"setting option_name. EXAMPLE: trace_errors.error_email", DeprecationWarning)