Better error message than

Can't locate object method "new" via package "Qpsmtpd::Plugin::logging::warn"
 (perhaps you forgot to load "Qpsmtpd::Plugin::logging::warn"?)
if plugin cannot be found in @plugin_dirs


git-svn-id: https://svn.perl.org/qpsmtpd/trunk@762 958fd67b-6ff1-0310-b445-bb7760255be9

lib/Qpsmtpd.pm

@@ -320,6 +320,9 @@ sub _load_plugin {
           last PLUGIN_DIR;
         }
       }
+      die "Plugin $plugin_name not found in our plugin dirs (",
+      	  join(", ", @plugin_dirs),")"
+        unless defined &{"${package}::plugin_name"};
     }
   }