Use stock gmaven plugin to achieve this

happen.

This happens because the version number isn't computed yet, but we try
to put that into HTTP header.

Fixing this by making <st:header/> tolerate null in value or name.

This reverts commit 0ef9424d.

Functioning JDK installation after the Oracle site change. They now put binaries behind SSO, so we need a real HTML scraper to be able to get past this, hence the htmlunit dependency.