Fix 07_custom_startup: .direct_classpath was remembered between executions

Change-Id: Icf519f1064f151fe46bdb6e42f9a54edb1bb8ef1
Reviewed-on: https://pirx.atteo.com/gerrit/553
Tested-by: Mr. Jenkins
Reviewed-by: Sławek Piotrowski <sentinel@atteo.com>