Update .travis.yml
Update .travis.yml

- Removed redis installation step.
  Redis is pre-installed:
   http://docs.travis-ci.com/user/ci-environment/#Data-Stores
- Run javadoc:javadoc to detect Javadoc tag errors
- Run on JDK8
- mvn install should be invoked on :install phase
  default :install phase executes mvn install
 - http://docs.travis-ci.com/user/languages/java/#Dependency-Management

o3project/odenos,machaharu/odenos,o3project/odenos,nis-sdn/odenos,y-higuchi/odenos,haizawa/odenos,narry/odenos,narry/odenos,haizawa/odenos,o3project/odenos,o3project/odenos,narry/odenos,machaharu/odenos,nis-sdn/odenos,y-higuchi/odenos,haizawa/odenos,nis-sdn/odenos,machaharu/odenos,o3project/odenos,nis-sdn/odenos,nis-sdn/odenos,haizawa/odenos,machaharu/odenos,narry/odenos,y-higuchi/odenos,y-higuchi/odenos,y-higuchi/odenos,haizawa/odenos,machaharu/odenos,narry/odenos