OAK-6655: Update travis build configuration
OAK-6655: Update travis build configuration

Use default MongoDB and Oracle JDK 8 version 

git-svn-id: 67138be12999c61558c3dd34328380c8e4523e73@1808125 13f79535-47bb-0310-9956-ffa450edef68

davidegiannella/jackrabbit-oak,davidegiannella/jackrabbit-oak,davidegiannella/jackrabbit-oak,davidegiannella/jackrabbit-oak,davidegiannella/jackrabbit-oak