Limit the .travis.yml to hibernate-search demos
Limit the .travis.yml to hibernate-search demos

Because others (OGM in particular) don't seem to build

hibernate/hibernate-demos,hibernate/hibernate-demos,hibernate/hibernate-demos,hibernate/hibernate-demos,DavideD/hibernate-demos,DavideD/hibernate-demos,DavideD/hibernate-demos,DavideD/hibernate-demos,hibernate/hibernate-demos,DavideD/hibernate-demos