Check to ensure Mdm is loaded to fix store_loot.

lib/msf/core/db_manager/host.rb

@@ -73,7 +73,7 @@ module Msf::DBManager::Host
   # address
   #
   def normalize_host(host)
-    return host if host.kind_of? ::Mdm::Host
+    return host if defined?(::Mdm) and host.kind_of? ::Mdm::Host
     norm_host = nil
 
     if (host.kind_of? String)
@@ -92,7 +92,7 @@ module Msf::DBManager::Host
       else
         norm_host = Rex::Socket.getaddress(host, true)
       end
-    elsif host.kind_of? ::Mdm::Session
+    elsif defined?(::Mdm) and host.kind_of? ::Mdm::Session
       norm_host = host.host
     elsif host.respond_to?(:session_host)
       # Then it's an Msf::Session object