Patch bloat.py to support du output.
Patch bloat.py to support du output.

For the purposes of a mounted Chrome OS image, du needs to be run as:

du -x -B 1

BUG=chromium-os:11432
TEST=manually ran the script and generated an R10 RC tree map.

Change-Id: I4ca649a3a5cd9fa2b4f7c36a4e2fba709677d049

Review URL: http://codereview.chromium.org/6303023

bpsinc-native/src_third_party_chromite,coreos/chromite,coreos/chromite,chadversary/chromiumos.chromite,zhang0137/chromite,chadversary/chromiumos.chromite,bpsinc-native/src_third_party_chromite,coreos/chromite,zhang0137/chromite,zhang0137/chromite,bpsinc-native/src_third_party_chromite