Issue 3393: Add javadocs stage to Travis (#3394)
Issue 3393: Add javadocs stage to Travis (#3394)

Adds a stage to the Travis configuration to build Javadocs.

Signed-off-by: Flavio Junqueira (fpj) <48c356ff4855e878e2050cfad72b47f4633a5eef@emc.com>
pravega/pravega,pravega/pravega,pravega/pravega