SotBE S18: make human ally AI protect its leader (Howgarth)

Since Howgarth may not die, this takes some randomness out of the
scenario.

data/campaigns/Son_Of_The_Black_Eye/scenarios/18_Northern_Alliance.cfg

@@ -159,6 +159,17 @@
         user_team_name=_ "Kapou’e"
         {GOLD 400 350 300}
         {FLAG_VARIANT loyalist}
+
+        [ai]
+            [goal]
+                name=protect_unit
+                [criteria]
+                    id="Howgarth III"
+                [/criteria]
+                protect_radius=12
+                value=20
+            [/goal]
+        [/ai]
     [/side]
 
     {STARTING_VILLAGES_AREA 6 57 27 13}