VM Updates (#83)

- Minor fixes to p4runtime exercise and README
- Adding p4runtime/solution
- Adding p4runtime/topology.json
- Updating .gitignore to include solution directory and topology.json
- Fixing root-bootstrap to exit on errors
- Updating VM name in Vagrantfile
- Setting up VM to automatically log 'p4' user in on startup

P4D2_2017_Fall/vm/Vagrantfile

@@ -3,7 +3,10 @@
 
 Vagrant.configure(2) do |config|
   config.vm.box = "bento/ubuntu-16.04"
+  config.vm.define "p4-tutorial" do |tutorial|
+  end
   config.vm.provider "virtualbox" do |vb|
+    vb.name = "P4 Tutorial" + Time.now.strftime(" %Y-%m-%d")
     vb.gui = true
     vb.memory = 2048
     vb.cpus = 2