Fixes bug #10974.

I didn't remove the few now redundant strings however, just in case
we'd want to use them after all for something.

data/campaigns/The_Rise_Of_Wesnoth/scenarios/16_Elf_Lords.cfg

@@ -163,6 +163,13 @@
     [option]
         message= _ "I think I'll fight the dragon!"
 
+        [show_if]
+            [variable]
+                name=the_dragon
+                numerical_equals=0
+            [/variable]
+        [/show_if]
+
         [command]
             [message]
                 description=Prince Haldric
@@ -195,6 +202,13 @@
     [option]
         message= _ "Let's get those saurians and nagas on that beach!"
 
+        [show_if]
+            [variable]
+                name=a_beach
+                numerical_equals=0
+            [/variable]
+        [/show_if]
+
         [command]
             [message]
                 description=Prince Haldric
@@ -227,6 +241,13 @@
     [option]
         message= _ "Let's clear out that troll hole!"
 
+        [show_if]
+            [variable]
+                name=troll_hole
+                numerical_equals=0
+            [/variable]
+        [/show_if]
+
         [command]
             [message]
                 description=Prince Haldric
@@ -258,6 +279,13 @@
     [option]
         message= _ "Let's put those souls to rest on the cursed isle!"
 
+        [show_if]
+            [variable]
+                name=cursed_isle
+                numerical_equals=0
+            [/variable]
+        [/show_if]
+
         [command]
             [message]
                 description=Prince Haldric