Added Time out

For some reason the handler was closing before the command could
complete.  Added the time out from bypassuac and now both psh and exe
work perfectly.

Author: jamesbcook

lib/msf/core/post/windows/runas.rb

@@ -30,5 +30,8 @@ def shell_execute_psh
   def shell_exec(command, args)
     print_status('Executing Command!')
     session.railgun.shell32.ShellExecuteA(nil, 'runas', command, args, nil, 'SW_SHOW')
+    ::Timeout.timeout(30) do
+      select(nil, nil, nil, 1) until session_created?
+    end
   end
 end