Support additional LocalSettings.php for mw-selenium jobs
Close PHP tag when appending LocalSettings.php in prepare-localhost
so other jobs can more safely append it as well.
Change to the working directory in bundle-with-options before running
the given initialization script. This will allow for mw-selenium
initialization code that is relative to the test directory.
See I4975a99f1c7d22c2f99f4557de4d7a081a5300f4 for slave-script changes.