Select NFS version with :nfs_version

lib/vagrant/action/vm/nfs.rb

@@ -91,7 +91,7 @@ module Vagrant
             key, opts = data
             opts[:map_uid] = prepare_permission(:uid, opts)
             opts[:map_gid] = prepare_permission(:gid, opts)
-            opts[:version] ||= 3
+            opts[:nfs_version] ||= 3
 
             acc[key] = opts
             acc

lib/vagrant/guest/linux.rb

@@ -60,7 +60,7 @@ module Vagrant
 
           # Do the actual creating and mounting
           @vm.channel.sudo("mkdir -p #{real_guestpath}")
-          @vm.channel.sudo("mount -o vers=#{opts[:version]} #{ip}:'#{opts[:hostpath]}' #{real_guestpath}",
+          @vm.channel.sudo("mount -o vers=#{opts[:nfs_version]} #{ip}:'#{opts[:hostpath]}' #{real_guestpath}",
                           :error_class => LinuxError,
                           :error_key => :mount_nfs_fail)
         end