Update docker network action to auto-generate cli flags

This commit updates the docker network behavior to auto-generate the
docker network command flags from Vagrants network config option.

plugins/providers/docker/action/network.rb

@@ -45,16 +45,16 @@ module VagrantPlugins
         def parse_cli_arguments(options)
           cli_opts = {create: [], connect: []}
 
-          # make this a function that generates the proper flags
+          # Splits the networking options to generate the proper CLI flags for docker
           if options[:type] != "dhcp"
-            if options[:docker__subnet]
+            options.each do |opt, value|
-              cli_opts[:create].concat(["--subnet", options[:docker__subnet]])
+              vals = opt.to_s.split("__")
-            end
+              if vals[0] == "docker" && vals.size == 3
-
+                cli_opts[vals[1].to_sym].concat(["--#{vals[2]}", value])
-            if options[:docker__ip]
+              end
-              cli_opts[:connect].concat(["--ip", options[:docker__ip]])
             end
           end
+
           return cli_opts
         end