Make mvanouwerkerk the OWNER of modules/geolocation

mvanouwerkerk is already an OWNER in the Chromium content/geolocation code,
so this seems like a natural fit.

R=abarth@chromium.org, mvanouwerkerk@chromium.org

Review URL: https://codereview.chromium.org/39593009

git-svn-id: svn://svn.chromium.org/blink/trunk@160493 bbb929c8-8fbe-4397-9dbb-9b2b20218538