Remove unnecessary apt source mangling

Author: benwebber

docker/jessie64/Dockerfile

@@ -9,9 +9,6 @@ ENV TERM=xterm
 # Defaults to graphical.target.
 RUN systemctl set-default multi-user.target
 
-RUN grep -rl httpredir.debian.org /etc/apt/sources.list* \
-    | xargs sed -i 's/httpredir.debian.org/ftp.us.debian.org/g'
-
 RUN apt-get update -y \
     && apt-get --no-install-recommends install -y \
       gcc \