Fix a missing ambient occlusion texture and uvmap revealed by 0766919645.

Reported in a video by: @psypherium
This was SVN commit r26827.

binaries/data/mods/public/art/actors/structures/persians/scout_tower.xml

@@ -7,16 +7,21 @@
         <texture file="structural/pers_struct.png" name="baseTex"/>
         <texture file="structural/pers_struct_norm.png" name="normTex"/>
         <texture file="structural/pers_struct_spec.png" name="specTex"/>
-        <texture file="structural/ao/pers_defense_tower.png" name="aoTex"/>
       </textures>
     </variant>
   </group>
   <group>
     <variant frequency="1" name="scouttowera">
       <mesh>structural/pers_scout_tower_a.dae</mesh>
+      <textures>
+        <texture file="structural/ao/pers_defense_tower.png" name="aoTex"/>
+      </textures>
     </variant>
     <variant frequency="1" name="scouttowerb">
       <mesh>structural/pers_scout_tower_b.dae</mesh>
+      <textures>
+        <texture file="structural/ao/pers_scout_tower_02.png" name="aoTex"/>
+      </textures>
     </variant>
   </group>
   <group>