Fix some issues with commands not referencing proper classes

lib/vagrant/cli.rb

@@ -32,12 +32,14 @@ module Vagrant
       # If we reached this far then we must have a subcommand. If not,
       # then we also just print the help and exit.
       command_class = nil
+      if @sub_command
         Vagrant.plugin("1").registered.each do |plugin|
           if plugin.command.has_key?(@sub_command.to_sym)
             command_class = plugin.command.get(@sub_command.to_sym)
             break
           end
         end
+      end
 
       if !command_class || !@sub_command
         help

plugins/command_reload/command.rb

@@ -5,7 +5,7 @@ require 'vagrant/command/start_mixins'
 module VagrantPlugins
   module CommandReload
     class Command < Vagrant::Command::Base
-      include StartMixins
+      include Vagrant::Command::StartMixins
 
       def execute
         options = {}

plugins/command_up/command.rb

@@ -5,7 +5,7 @@ require 'vagrant/command/start_mixins'
 module VagrantPlugins
   module CommandUp
     class Command < Vagrant::Command::Base
-      include StartMixins
+      include Vagrant::Command::StartMixins
 
       def execute
         options = {}