chore(builder): upgrade to docker 0.9.1

Author: Gabriel Monroy

builder/Dockerfile

@@ -13,8 +13,8 @@ RUN mkdir -p /var/run/sshd
 RUN apt-get install -yq aufs-tools iptables ca-certificates lxc
 RUN echo "deb http://get.docker.io/ubuntu docker main" > /etc/apt/sources.list.d/docker.list
 RUN apt-key adv --keyserver keyserver.ubuntu.com --recv-keys 36A1D7869245C8950F966E92D8576A8BA88D21E9
-RUN apt-get update -q
-RUN apt-get install -yq lxc lxc-docker-0.9.0
+RUN apt-get update -qy
+RUN apt-get install -yq lxc-docker-0.9.1
 
 # install recent pip
 RUN wget -qO- https://raw.github.com/pypa/pip/1.5.4/contrib/get-pip.py | python -