Fix warnings
Fix warnings

Child attribute was being instantiated before parent attribute, gives warnings under GCC 4.9.1
lightslife/cppformat,dean0x7d/cppformat,alabuzhev/fmt,cppformat/cppformat,alabuzhev/fmt,Jopie64/cppformat,Jopie64/cppformat,mojoBrendan/fmt,wangshijin/cppformat,alabuzhev/fmt,cppformat/cppformat,cppformat/cppformat,mojoBrendan/fmt,Jopie64/cppformat,dean0x7d/cppformat,wangshijin/cppformat,dean0x7d/cppformat,lightslife/cppformat,wangshijin/cppformat,mojoBrendan/fmt,lightslife/cppformat