Revert "hmm, I hate it if these things work locally..."

This reverts commit 4cebe423.

script/ci/before_install.sh

 #!/bin/sh
-# install selenium prerelease
-gem install selenium-webdriver --pre
-gem list
 
 # Ensure known RubyGems version
 envdir="$(readlink -e $(dirname $0))/../env"
 . "$envdir/ruby_env"
 . "$envdir/ensure_right_rubygems"
 
+# install selenium prerelease
+gem install selenium-webdriver --pre