Set default auto-commit to true in default configuration

f5de0b3f02d3177561303d9fee1d3b5dbead440b recently changed the default in the field initializer, however the default configuration in bonecp-default-config.xml resets default auto-commit back to false. Thus f5de0b3f02d3177561303d9fee1d3b5dbead440b did not have the intended effect.