PyAuto import tests: Do not import from firefox if it's not installed
PyAuto import tests: Do not import from firefox if it's not installed

Bail out the firefox import tests if firefox is not installed on win.

BUG=
TEST=

Review URL: http://codereview.chromium.org/3549015

git-svn-id: http://src.chromium.org/svn/trunk/src@61708 4ff67af0-8c30-449e-8e8b-ad334ec8d88c

Former-commit-id: 093092e8943ba33c6b22a4e5c931fe6d856057de
meego-tablet-ux/meego-app-browser,meego-tablet-ux/meego-app-browser,meego-tablet-ux/meego-app-browser,meego-tablet-ux/meego-app-browser,meego-tablet-ux/meego-app-browser,meego-tablet-ux/meego-app-browser,meego-tablet-ux/meego-app-browser,meego-tablet-ux/meego-app-browser,meego-tablet-ux/meego-app-browser,meego-tablet-ux/meego-app-browser