Restrict "shield" subtype to effects with a limited damage absorption total.

@@ -3664,7 +3664,7 @@ newEffect{
 	desc = _t"Stone Link",
 	long_desc = function(self, eff) return ("The target protects all those around it in radius %d by redirecting all damage against them to itself."):tformat(eff.rad) end,
 	type = "physical",
-	subtype = { earth=true, shield=true },
+	subtype = { earth=true },
 	status = "beneficial",
 	parameters = { rad=3 },
 	on_gain = function(self, err) return ("#Target# begins protecting %s friends with a stone shield."):tformat(string.his_her(self)), _t"+Stone Link" end,
@@ -3693,7 +3693,7 @@ newEffect{
 	desc = _t"Stone Link",
 	long_desc = function(self, eff) return ("The target is protected by %s, redirecting all damage to it."):tformat(eff.src:getName()) end,
 	type = "physical",
-	subtype = { earth=true, shield=true },
+	subtype = { earth=true },
 	status = "beneficial",
 	parameters = { },
 	on_gain = function(self, err) return _t"#Target# is protected by a stone shield.", _t"+Stone Link" end,