change repo ref to https

Gemfile

@@ -7,11 +7,11 @@ group :development do
   # We depend on Vagrant for development, but we don't add it as a
   # gem dependency because we expect to be installed within the
   # Vagrant environment itself using `vagrant plugin`.
-  gem "vagrant", :git => "git://github.com/mitchellh/vagrant.git"
+  gem 'vagrant', :git => 'https://github.com/mitchellh/vagrant.git'
   gem 'pry'
 end
 
 group :plugins do
-  gem "vagrant-libvirt", :path => '.'
+  gem 'vagrant-libvirt', :path => '.'
 end