Revert 240682 "Add libc++ and libc++abi to third-party."

Revert 240682 "Add libc++ and libc++abi to third-party."

This change broke deps2git.  We will add the repos in a bit and
we'll add check_deps2git to the CQ.

> Add libc++ and libc++abi to third-party.
> 
> BUG=318770, 313751
> R=glider@chromium.org,thakis@chromium.org,bradnelson@chromium.org,darin@chromium.org
> 
> Review URL: https://codereview.chromium.org/75213003

TBR=alextaran@chromium.org

Committed: https://src.chromium.org/viewvc/chrome?view=rev&revision=240706

[cmp, 2013-12-13 18:45:50]

Committed patchset #1 manually as r240706.