Merge pull request #124 from fundon/delete-superfluous-variable

delete superfluous environment variables

dockerfiles/images/redis/Dockerfile

@@ -3,8 +3,6 @@ MAINTAINER  Meaglith Ma <genedna@gmail.com> (@genedna), Lance Ju <juzhenatpku@gm
 
 ENV         DEBIAN_FRONTEND noninteractive
 
-ENV         DEBIAN_FRONTEND noninteractive
-
 RUN         apt-get update && apt-get install -y redis-server
 # Usually redis doesn't need a password
 #RUN         sed -i "s/# requirepass foobared/requirepass THE_REDIS_PASSWORD/g" /etc/redis/redis.conf