Remove unnecessary exclusion rules from web.gyp.

They should not be necessary anymore, since config.gyp:config already provides
more generic rules matching them and web.gyp:webkit already depends on config.

BUG=None
TEST=build still works.
R=abarth@chromium.org

Review URL: https://codereview.chromium.org/47833002

git-svn-id: svn://svn.chromium.org/blink/trunk@160745 bbb929c8-8fbe-4397-9dbb-9b2b20218538