More base_url_consistency.

Continuation of [016e2b1d131e7fd9dd482f76f019a448adb880ef]:
Some place even added a slash, replaced that with options.url_path()
instead of options.value() to force a trailing slash.

The c_nginxconf and c_apacheconf modules use options.value, but they
need the url without the trailing slash. So didn't change that.