Save ref names for easier debugging

lib/msf/core/db_manager/exploit_attempt.rb

@@ -118,15 +118,17 @@ module Msf::DBManager::ExploitAttempt
       username   = opts.delete(:username)
       mname      = opts.delete(:module)
 
-      if not vuln
-        # Create a references map from the module list
-        ref_objs = ::Mdm::Ref.where(:name => mrefs.map { |ref|
+      if ! vuln.nil?
+        ref_names = mrefs.map { |ref|
           if ref.respond_to?(:ctx_id) and ref.respond_to?(:ctx_val)
             "#{ref.ctx_id}-#{ref.ctx_val}"
           else
             ref.to_s
           end
-        })
+        }
+
+        # Create a references map from the module list
+        ref_objs = ::Mdm::Ref.where(name: ref_names)
 
         # Try find a matching vulnerability
         vuln = find_vuln_by_refs(ref_objs, host, svc)