[chromedriver] Don't catch exceptions raised during quit.

It's better to terminate the entire test. Especially on Android,
if quit doesn't succeed, subsequent tests will fail to create a session
since the device is not freed.

BUG=None
R=kkania@chromium.org

Review URL: https://codereview.chromium.org/27420005

git-svn-id: http://src.chromium.org/svn/trunk/deps/third_party/webdriver@228958 4ff67af0-8c30-449e-8e8b-ad334ec8d88c
3 files changed