Do not vendor cookbooks using Berkshelf anymore

Instead, use the Berkshelf support in knife-solo and the
vagrant-berkshelf plugin on Vagrant

cookbooks/nginx/libraries/nginx_version.rb

@@ -1,37 +0,0 @@
-class NginxVersion
-  include Comparable
-
-  attr_reader :version
-
-  def initialize(version)
-    @version = version
-  end
-
-  def <=>(other)
-    lhsegments = segments
-    rhsegments = other.segments
-
-    parts = [lhsegments.size, rhsegments.size].max
-
-    (0..(parts - 1)).each do |index|
-      lhs = lhsegments[index] || 0
-      rhs = rhsegments[index] || 0
-
-      next if lhs == rhs
-
-      return lhs <=> rhs
-    end
-
-    0
-  end
-
-  def to_s
-    version
-  end
-
-  protected
-
-  def segments
-    version.split('.').map { |part| Integer(part) }
-  end
-end