Vagrantfile: Bail out of provisioning if anything fails
If something fails to install in the provisioning script, the script
currently continues, burying the error in the log.
`set -e` means the shell exits with an error if any command fails.
diff --git a/Vagrantfile b/Vagrantfile
index 86c95ac..f45c011 100644
--- a/Vagrantfile
+++ b/Vagrantfile
@@ -14,6 +14,8 @@
config.vm.network "forwarded_port", guest: 8888, host: 8888
config.vm.provision "shell", inline: <<-SHELL
+ set -e
+
sudo apt-get update
sudo apt-get install -y autoconf automake build-essential expect git \
libfreetype6-dev libpng12-dev libtool nmap openjdk-7-jdk \