Update gs.py to support new versions of Google Storage.
Update gs.py to support new versions of Google Storage.

New versions of Google Storage use a different format for uploading
files. Update gs.py to support both the new and old formats.

BUG=none
TEST=Try it with new version of gsutil. Run simple chrome with it.

Change-Id: I0ae63151795c82e6c9fefa90a6ed428ba736cd40
Reviewed-on: https://chromium-review.googlesource.com/171987
Reviewed-by: Matt Tennant <46e612415b446ccde19638e4035892001c237942@chromium.org>
Tested-by: David James <f231dc574bbeb62604660cbc162d1b8642a0a3af@chromium.org>
Commit-Queue: David James <f231dc574bbeb62604660cbc162d1b8642a0a3af@chromium.org>

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