[chromedriver] Strip symbols out of chromedriver binaries for Linux

BUG=chromedriver:697
NOTRY=true

Review URL: https://codereview.chromium.org/267503007

git-svn-id: svn://svn.chromium.org/chrome/trunk/src@267410 0039d316-1c4b-4281-b951-d872f2087c98