suppress warning on win8.1 sdk

Else,

src\disk_interface.cc(87) : error C2220: warning treated as error - no 'object' file generated
src\disk_interface.cc(87) : warning C4996: 'GetVersionExA': was declared deprecated
        C:\Program Files (x86)\Windows Kits\8.1\include\um\sysinfoapi.h(433) : see declaration of 'GetVersionExA'