Add check for modules registering a DEBUG option

Author: jvazquez-r7

tools/msftidy.rb

@@ -610,6 +610,15 @@ def check_print_debug
     end
   end
 
+  # Check for modules registering the DEBUG datastore option
+  #
+  # @see https://github.com/rapid7/metasploit-framework/issues/3816
+  def check_datastore_debug
+    if @source =~ /Opt.*\.new\('(?i)DEBUG(?-i)'/
+      error('Please don\'t register a DEBUG datastore option, it has an special meaning and is used for development')
+    end
+  end
+
   private
 
   def load_file(file)
@@ -660,6 +669,7 @@ def run_checks(full_filepath)
   tidy.check_udp_sock_get
   tidy.check_invalid_url_scheme
   tidy.check_print_debug
+  tidy.check_datastore_debug
   return tidy
 end