Update Dockerfile

Dockerfile

@@ -9,11 +9,6 @@
 FROM haproxytech/haproxy-debian:2.7
 
 # Install Haproxy.
-RUN \
-  sed -i 's/^# \(.*-backports\s\)/\1/g' /etc/apt/sources.list && apt-get update && \
-  #apt-get install -y haproxy=1.5.3-1~ubuntu14.04.1 && \
-  sed -i 's/^ENABLED=.*/ENABLED=1/' /etc/default/haproxy && \
-  rm -rf /var/lib/apt/lists/*
 
 # Add files.
 ADD haproxy.cfg /etc/haproxy/haproxy.cfg