Make unloadable

src/com/dmdirc/addons/ui_dummy/plugin.config

@@ -14,6 +14,7 @@ metadata:
   description=A dummy user interface that allows no interaction
   name=ui_dummy
   nicename=Dummy UI
+  unloadable=no
 
 updates:
   id=41

src/com/dmdirc/addons/ui_swing/plugin.config

@@ -14,6 +14,7 @@ metadata:
   description=The standard DMDirc user interface
   name=ui_swing
   nicename=Swing UI
+  unloadable=no
 
 updates:
   id=42