Correct libcxx{abi} revision in buildtools/DEPS

libcxxabi_revision was incorrectly updated instead of libcxx_revision in this
CL: https://chromium-review.googlesource.com/c/chromium/src/+/1516275

TBR=thakis,dpranke

Change-Id: I72e8710752159de434e1dfdafe3895a688b33fc1
Reviewed-on: https://chromium-review.googlesource.com/c/chromium/src/+/1520361
Reviewed-by: Thomas Anderson <thomasanderson@chromium.org>
Reviewed-by: Nico Weber <thakis@chromium.org>
Commit-Queue: Thomas Anderson <thomasanderson@chromium.org>
Cr-Commit-Position: refs/heads/master@{#640406}
1 file changed