Updated Vagrantfile to install more recent versions of software.

Quieted the apt-get installs to reduce terminal output chaos.

Changed the rvm GPG key server to remove the expired key warning
when the rvm public key is used to verify the rvm download. Command
used conforms to that specified by rvm.io.

Ruby and bundler versions are read from Vagrant's gemspec and used
with rvm to download the latest Ruby version that complies with
the version constraint. Exact bundler version is installed according
to gemspec.

Rubygems is upgraded to latest version through rvm.

Vagrantfile

@@ -25,43 +25,49 @@ Vagrant.configure("2") do |config|
   end
 end
 
-$shell = <<-CONTENTS
+$shell = <<-'CONTENTS'
 export DEBIAN_FRONTEND=noninteractive
 MARKER_FILE="/usr/local/etc/vagrant_provision_marker"
+RUBY_VER_REQ=$(awk '$1 == "s.required_ruby_version" { print $4 }' /vagrant/vagrant.gemspec | tr -d '"')
+BUNDLER_VER_REQ=$(awk '/s.add_dependency "bundler"/ { print $4 }' /vagrant/vagrant.gemspec | tr -d '"')
 
 # Only provision once
 if [ -f "${MARKER_FILE}" ]; then
   exit 0
 fi
 
 # Update apt
-apt-get update
+apt-get update --quiet
 
 # Install basic dependencies
-apt-get install -y build-essential bsdtar curl
+apt-get install -qy build-essential bsdtar curl
 
 # Import the mpapis public key to verify downloaded releases
-su -l -c 'curl -sSL https://rvm.io/mpapis.asc | gpg -q --import -' vagrant
+su -l -c 'gpg --keyserver hkp://keys.gnupg.net --recv-keys 409B6B1796C275462A1703113804BB82D39DC0E3' vagrant
 
 # Install RVM
 su -l -c 'curl -sL https://get.rvm.io | bash -s stable' vagrant
 
 # Add the vagrant user to the RVM group
 #usermod -a -G rvm vagrant
 
-# Install some Rubies
-su -l -c 'rvm install 2.2.3' vagrant
-su -l -c 'rvm --default use 2.2.3' vagrant
+# Install latest Ruby that complies with Vagrant's version constraint
+RUBY_VER_LATEST=$(su -l -c 'rvm list known' vagrant | tr '[]-' ' ' | awk "/^ ruby  ${RUBY_VER_REQ:0:1}\./ { print \$2 }" | sort | tail -n1)
+su -l -c "rvm install ${RUBY_VER_LATEST}" vagrant
+su -l -c "rvm --default use ${RUBY_VER_LATEST}" vagrant
 
 # Output the Ruby version (for sanity)
 su -l -c 'ruby --version' vagrant
 
 # Install Git
-apt-get install -y git
+apt-get install -qy git
 
-# Prepare to run unit tests
-su -l vagrant -c 'gem install bundler -v 1.12.5'
-su -l vagrant -c 'cd /vagrant; bundle install'
+# Upgrade Rubygems
+su -l -c "rvm ${RUBY_VER_LATEST} do gem update --system" vagrant
+
+# Install bundler and prepare to run unit tests
+su -l -c "gem install bundler -v ${BUNDLER_VER_REQ}" vagrant
+su -l -c 'cd /vagrant; bundle install' vagrant
 
 # Automatically move into the shared folder, but only add the command
 # if it's not already there.