YARN-3248. Moving it to improvements section in CHANGES.txt.
YARN-3248. Moving it to improvements section in CHANGES.txt.

(cherry picked from commit df52ff92ae42977bc743630191d1cbe1e17d00cf)

mix/hadoop,mix/hadoop,myeoje/PhillyYarn,myeoje/PhillyYarn,myeoje/PhillyYarn,myeoje/PhillyYarn,mix/hadoop,mix/hadoop,mix/hadoop,myeoje/PhillyYarn,mix/hadoop,myeoje/PhillyYarn,myeoje/PhillyYarn,myeoje/PhillyYarn,mix/hadoop,mix/hadoop