rs-identify: fix -Wzero-as-null-pointer-constant in _WIN32 code
rs-identify: fix -Wzero-as-null-pointer-constant in _WIN32 code

darktable-org/rawspeed,darktable-org/rawspeed,LebedevRI/rawspeed,LebedevRI/rawspeed,darktable-org/rawspeed,LebedevRI/rawspeed,LebedevRI/rawspeed,darktable-org/rawspeed,LebedevRI/rawspeed,darktable-org/rawspeed