Minor improvements to vagrant VMs

* disable the default Vagrant shared folder, which we don't need
 * install `bc` on the dev VM, since it's needed by the smoke tests
 * expose the dev VM docker on TCP, for convenience

Vagrantfile

@@ -1,7 +1,7 @@
 VAGRANTFILE_API_VERSION = "2"
 
 vm_ip = "172.16.0.3" # arbitrary private IP
-pkgs = "lxc-docker build-essential ethtool libpcap-dev git mercurial"
+pkgs = "lxc-docker build-essential ethtool libpcap-dev git mercurial bc"
 
 Vagrant.configure(VAGRANTFILE_API_VERSION) do |config|
   config.vm.box = "phusion/ubuntu-14.04-amd64"
@@ -9,7 +9,9 @@ Vagrant.configure(VAGRANTFILE_API_VERSION) do |config|
 
   config.vm.network "private_network", ip: vm_ip
 
-  config.vm.synced_folder "./", "/home/vagrant/src/github.com/zettio/weave"
+  config.vm.synced_folder ".", "/vagrant", disabled: true
+  config.vm.synced_folder ".", "/home/vagrant/src/github.com/zettio/weave"
+  config.vm.provision :shell, :inline => "ln -s /home/vagrant/src/github.com/zettio/weave /home/vagrant/weave"
 
   config.vm.provision :shell, :inline => "sudo apt-key adv --keyserver hkp://keyserver.ubuntu.com:80 --recv-keys 36A1D7869245C8950F966E92D8576A8BA88D21E9"
   config.vm.provision :shell, :inline => "echo deb https://get.docker.io/ubuntu docker main > /etc/apt/sources.list.d/docker.list"
@@ -28,6 +30,9 @@ Vagrant.configure(VAGRANTFILE_API_VERSION) do |config|
   config.vm.provision :shell, :inline => "chown -R vagrant:vagrant /home/vagrant/src"
   config.vm.provision :shell, :inline => "/usr/local/go/bin/go clean -i net; /usr/local/go/bin/go install -tags netgo std"
 
+  config.vm.provision :shell, :inline => "echo 'DOCKER_OPTS=\"-H unix:///var/run/docker.sock -H tcp://0.0.0.0:2375\"' >> /etc/default/docker"
+  config.vm.provision :shell, :inline => "service docker restart"
+
 end
 
 begin

test/Vagrantfile

@@ -14,7 +14,7 @@ def configure_docker(host, hostname, ip)
   host.vm.hostname = hostname
   host.vm.network "private_network", ip: ip
 
-  # host.vm.synced_folder "./", "/home/vagrant/src/github.com/zettio/weave"
+  host.vm.synced_folder ".", "/vagrant", disabled: true
 
   host.vm.provision :shell, :inline => "sudo apt-key adv --keyserver hkp://keyserver.ubuntu.com:80 --recv-keys 36A1D7869245C8950F966E92D8576A8BA88D21E9"
   host.vm.provision :shell, :inline => "echo deb https://get.docker.io/ubuntu docker main > /etc/apt/sources.list.d/docker.list"