Fix Travis build by decreasing unnecessary logging
Fix Travis build by decreasing unnecessary logging

Fixes https://github.com/google/closure-compiler/issues/3568

-------------
Created by MOE: https://github.com/google/moe
MOE_MIGRATED_REVID=300175046

google/closure-compiler,nawawi/closure-compiler,monetate/closure-compiler,google/closure-compiler,Yannic/closure-compiler,monetate/closure-compiler,monetate/closure-compiler,vobruba-martin/closure-compiler,nawawi/closure-compiler,vobruba-martin/closure-compiler,Yannic/closure-compiler,nawawi/closure-compiler,ChadKillingsworth/closure-compiler,ChadKillingsworth/closure-compiler,vobruba-martin/closure-compiler,ChadKillingsworth/closure-compiler,Yannic/closure-compiler,google/closure-compiler,nawawi/closure-compiler,Yannic/closure-compiler,google/closure-compiler,ChadKillingsworth/closure-compiler,monetate/closure-compiler,vobruba-martin/closure-compiler