Run 'mvn clean' in bootstrap script.
Run 'mvn clean' in bootstrap script.

- Otherwise, scala classes can in rare cases  be missing from
  the installed artifact.

vespa-engine/vespa,vespa-engine/vespa,vespa-engine/vespa,vespa-engine/vespa,vespa-engine/vespa,vespa-engine/vespa,vespa-engine/vespa,vespa-engine/vespa,vespa-engine/vespa,vespa-engine/vespa