参考：http://stackoverflow.com/questions/21031491/core-data-info-error-in-console-at-runtime
INFO: fetch-response is unable to open the file /Users/userName/Library/Application Support/iPhone Simulator/7.0.3/Applications/964A590B-7131-4BAE-958B-1783BEC193EF/Library/Caches/userName.AppName/fsCachedData/2F1A8708-35A9-491E-9C21-154BA428CA10. Errno: 2