fix typo in c++ header check

Change-Id: Ibb4dd0abe104ea5e6d46c7deb1ef0856e7cfda51
Reviewed-on: https://skia-review.googlesource.com/138991
Auto-Submit: Mike Klein <mtklein@chromium.org>
Commit-Queue: Brian Osman <brianosman@google.com>
Reviewed-by: Brian Osman <brianosman@google.com>
1 file changed