some fixes and improvements to bootstrap

bootstrap.sh

@@ -1,17 +1,15 @@
 DOKKU_REPO=${DOKKU_REPO:-"https://github.com/progrium/dokku.git"}
 DOKKU_STACK=${DOKKU_STACK:-"https://s3.amazonaws.com/progrium-dokku/progrium_buildstep.tgz"}
 DOCKER_PKG=${DOCKER_PKG:-"https://launchpad.net/~dotcloud/+archive/lxc-docker/+files/lxc-docker_0.4.2-1_amd64.deb"}
+set -e
 
 apt-get update
-apt-get install -y linux-image-extra-`uname -r`
-apt-get install -y python-software-properties
+DEBIAN_FRONTEND=noninteractive apt-get install -y linux-image-extra-`uname -r`
 apt-get install -y git nginx make curl dnsutils
 
-cd /tmp
-wget "$DOCKER_PKG"
-dpkg -i lxc-docker_0.4.2-1_amd64.deb
-apt-get install -f -y
-rm lxc-docker_0.4.2-1_amd64.deb
+wget -qO- "$DOCKER_PKG" > /tmp/lxc-docker_0.4.2-1_amd64.deb
+dpkg --force-depends -i /tmp/lxc-docker_0.4.2-1_amd64.deb && apt-get install -f -y
+rm /tmp/lxc-docker_0.4.2-1_amd64.deb
 
 sed -i.bak 's/docker -d/docker -d -r=true/' /etc/init/docker.conf # Docker should restart containers