Update to latest vagrant version

(which deprecated rubygems based installation)

Gemfile

-source 'https://rubygems.org'
-gem 'vagrant'
\ No newline at end of file

Gemfile.lock

-GEM
-  remote: https://rubygems.org/
-  specs:
-    archive-tar-minitar (0.5.2)
-    childprocess (0.3.9)
-      ffi (~> 1.0, >= 1.0.11)
-    erubis (2.7.0)
-    ffi (1.6.0)
-    i18n (0.6.4)
-    json (1.7.7)
-    log4r (1.1.10)
-    net-scp (1.0.4)
-      net-ssh (>= 1.99.1)
-    net-ssh (2.2.2)
-    vagrant (1.0.7)
-      archive-tar-minitar (= 0.5.2)
-      childprocess (~> 0.3.1)
-      erubis (~> 2.7.0)
-      i18n (~> 0.6.0)
-      json (>= 1.5.1, < 1.8.0)
-      log4r (~> 1.1.9)
-      net-scp (~> 1.0.4)
-      net-ssh (~> 2.2.2)
-
-PLATFORMS
-  ruby
-
-DEPENDENCIES
-  vagrant

Readme.md

@@ -24,11 +24,7 @@ git clone https://gitlab.eox.at/vagrant/builder_rpm.git ./
 
 ```
 
-Install vagrant, either see [vagrant docs](http://docs.vagrantup.com/v1/docs/getting-started/index.html) for more information, or install the latest version via rubygems by running the following command
-
-```bash
-bundle install
-```
+Previously you could install vagrant via rubygems (e.g. using bundler), but since 1.1.x this method is deprecated, so please go to http://downloads.vagrantup.com/ and download the latest package for your operating system
 
 Edit the _Vagrantfile_ and update the project (see the beginning of [Vagrantfile](/vagrant/builder_rpm/tree/master/Vagrantfile))