only use logger after logger configuration (fix #873)
fix code style
Fix .travis.yml
Merge pull request #877 from suma/fix-travis

Fix .travis.yml
Merge pull request #875 from jubatus/fix-873

Use logger macros only after configuring logger
only use logger after logger configuration in jubavisor (fix #873)
Merge pull request #878 from jubatus/fix-873-jubavisor

only use logger after logger configuration in jubavisor (fix #873)