Fix issues detected by Travis build config validation (#1980)
Fix issues detected by Travis build config validation (#1980)

* Fix Travis error about conflicting "matrix" and "jobs" keys

Travis says "both matrix and jobs given, matrix overwrites jobs".

* Fix Travis warning about deprecated key "sudo"

Travis says "deprecated key sudo (The key `sudo` has no effect anymore.)"

* Fix Travis message about redis-server being an alias for redis

Travis says "redis-server is an alias for redis, using redis".
google/trillian,RJPercival/trillian,AlCutter/trillian,google/trillian,RJPercival/trillian,gdbelvin/trillian,gdbelvin/trillian,AlCutter/trillian,gdbelvin/trillian