Tweak the damage of the mess monster

Try for 7 damages when hit with a mess_arrow a player (by a
mese_monster)

mods/mobs/mese_monster.lua

@@ -82,7 +82,7 @@ mobs:register_arrow("mobs:mese_arrow", {
 
 		player:punch(self.object, 1.0,  {
 			full_punch_interval=1.0,
-			damage_groups = {fleshy=1},
+			damage_groups = {fleshy=7},
 		}, 0) -- {x=s.x-p.x, y=s.y-p.y, z=s.z-p.z})
 	end,