libaom: drop clang-format from cmake_update.sh

Having a local version of clang-format v7.0.1 fails due to differences
in chromium/src/.clang_format.

This is redundant anyway since it is covered by git cl format at the end
of cmake_update.sh

Change-Id: I58ae0ab1dcdda3c6c91b83e8402c6bdf05f2e106
Reviewed-on: https://chromium-review.googlesource.com/c/chromium/src/+/1610430
Auto-Submit: Johann Koenig <johannkoenig@google.com>
Reviewed-by: James Zern <jzern@google.com>
Reviewed-by: Tom Finegan <tomfinegan@chromium.org>
Commit-Queue: Johann Koenig <johannkoenig@google.com>
Cr-Commit-Position: refs/heads/master@{#659663}
1 file changed