Remove platform_DiskIterate test due to removal of DeviceKit-Disks

BUG=chromium-os:14576
TEST=Built and ran test

Change-Id: I88a56af8207083934235932d582c4bfc28ab6016

R=dalecurtis@chromium.org

Review URL: http://codereview.chromium.org/6905061
3 files changed