Fix event handlers on ruby 2

Fixes rapid7#4219

Author: egypt

lib/msf/core/event_dispatcher.rb

@@ -176,7 +176,7 @@ def method_missing(name, *args)
     found = false
     case event
     when "on"
-      if respond_to?(subscribers)
+      if respond_to?(subscribers, true)
         found = true
         self.send(subscribers).each do |sub|
           next if not sub.respond_to?(name)
@@ -221,11 +221,11 @@ def remove_event_subscriber(array, subscriber) # :nodoc:
     array.delete(subscriber)
   end
 
-  attr_accessor :general_event_subscribers # :nodoc:
   attr_accessor :custom_event_subscribers # :nodoc:
+  attr_accessor :db_event_subscribers # :nodoc:
   attr_accessor :exploit_event_subscribers # :nodoc:
+  attr_accessor :general_event_subscribers # :nodoc:
   attr_accessor :session_event_subscribers # :nodoc:
-  attr_accessor :db_event_subscribers # :nodoc:
   attr_accessor :ui_event_subscribers # :nodoc:
 
 end

lib/msf/core/payload.rb

@@ -449,7 +449,6 @@ def compatible_nops
   #
   def on_session(session)
 
-
     # If this payload is associated with an exploit, inform the exploit
     # that a session has been created and potentially shut down any
     # open sockets. This allows active exploits to continue hammering

plugins/event_tester.rb

@@ -21,17 +21,19 @@ def name; "event_tester"; end
   def initialize(framework, opts)
     super
     @subscriber = Subscriber.new
+    framework.events.add_custom_subscriber(@subscriber)
+    framework.events.add_db_subscriber(@subscriber)
     framework.events.add_exploit_subscriber(@subscriber)
-    framework.events.add_session_subscriber(@subscriber)
     framework.events.add_general_subscriber(@subscriber)
-    framework.events.add_db_subscriber(@subscriber)
+    framework.events.add_session_subscriber(@subscriber)
     framework.events.add_ui_subscriber(@subscriber)
   end
   def cleanup
+    framework.events.remove_custom_subscriber(@subscriber)
+    framework.events.remove_db_subscriber(@subscriber)
     framework.events.remove_exploit_subscriber(@subscriber)
-    framework.events.remove_session_subscriber(@subscriber)
     framework.events.remove_general_subscriber(@subscriber)
-    framework.events.remove_db_subscriber(@subscriber)
+    framework.events.remove_session_subscriber(@subscriber)
     framework.events.remove_ui_subscriber(@subscriber)
   end
 end