upload_image.sh to support streamOptimized disks

The current version of the script will use "preallocated" as the
disk type of a stream optimized disk. This needs to be fixed by
introspecting the createType of the vmdk file.

Closes-Bug: #1275993

Change-Id: I98594acecf26dd1164870f43890254a19ef23fe9
Merge "upload_image.sh to support streamOptimized disks"