Fix Tools/Scripts/check-blink-deps

Chromium's checkdeps.py has moved but the
script was never updated.

TEST=Manually run the script and it works!

Review URL: https://codereview.chromium.org/325473003

git-svn-id: svn://svn.chromium.org/blink/trunk@175733 bbb929c8-8fbe-4397-9dbb-9b2b20218538