Add none support to ProxyJump

lib/net/ssh/config.rb

@@ -155,6 +155,9 @@ def load(path, host, settings = {}, base_dir = nil)
             %w[proxyjump proxycommand].each do |proxy_key|
               if (proxy_value = settings.delete(proxy_key))
                 settings['proxy'] ||= [proxy_key, proxy_value]
+                if proxy_key == 'proxyjump' and proxy_value == 'none'
+                  settings.delete('proxy')
+                end
               end
             end
           end

lib/net/ssh/proxy/jump.rb

@@ -43,9 +43,11 @@ def build_proxy_command_equivalent(connection_options = nil)
           template << " -p #{uri.port}"    if uri.port
           template << " -J #{extra_jumps}" if extra_jumps
           template << " -F #{config}" if config != true && config
-          template << " -W %h:%p "
-          template << uri.host
-
+          # When ProxyJump is set to none explicity disable the jumphost
+          unless uri.host == 'none'
+            template << " -W %h:%p "
+            template << uri.host
+          end
           @command_line_template = template
         end
       end

test/test_proxy_jump.rb

@@ -7,6 +7,12 @@ def test_is_a_proxy_command
     assert proxy.is_a?(Net::SSH::Proxy::Command)
   end
 
+  def test_proxy_none
+     proxy = Net::SSH::Proxy::Jump.new("none")
+     proxy.build_proxy_command_equivalent
+     assert_equal "ssh", proxy.command_line_template
+  end
+
   def test_host
     proxy = Net::SSH::Proxy::Jump.new("jumphost")
     proxy.build_proxy_command_equivalent