Fix missing drive sizes in macOS Sierra
Fix missing drive sizes in macOS Sierra

In this new macOS version, `diskutil info` outputs the drive size using
"Disk Size" instead of "Total Size".

Signed-off-by: Juan Cruz Viotti <8493db2a4f45d66df375afe12f7eba59fe1c8d78@gmail.com>

resin-io-modules/drivelist,resin-io-modules/drivelist,resin-io/drivelist,resin-io-modules/drivelist,resin-io-modules/drivelist,resin-io/drivelist