HttT S15: Add a hint about the Guardsmen.

(cherry picked from commit 4a76d0b9b3)

data/campaigns/Heir_To_The_Throne/scenarios/15_The_Lost_General.cfg

@@ -480,6 +480,9 @@
             speaker=unit
             message= _ "We are desperately trying to rid these tunnels of orcs and trolls! Please help us in our quest."
         [/message]
+#ifdef EASY
+        {NARRATOR_MESSAGE (_ "The dwarves are your allies in this scenario. If you help them survive the battle, they may provide you with useful information.")}
+#endif
     [/event]
 
     [event]