change compilation order to workaround windows issue.
change compilation order to workaround windows issue.

Sometimes on windows, no java sources are sent to the
aggressive compiler when there are no scala sources.

Stexxen/activator-akka-distributed-workers-java,typesafehub/activator-akka-distributed-workers-java,Stexxen/activator-akka-distributed-workers-java,typesafehub/activator-akka-distributed-workers-java