Update some maps with new terrains

Patch by: @wowgetoffyourcellphone
- syria_2p
- sporades_islands_2p
- saharan_oases_4p
- butana_steppe_2p
- bactria_2p
- alpine_valleys_2p
- belgian_bog_2p

This was SVN commit r25560.

binaries/data/mods/public/art/actors/geology/metal_india_round.xml

@@ -3,12 +3,10 @@
   <castshadow/>
   <group>
     <variant frequency="1" name="Metal Mine Round India">
-      <variant name="props">
-        <props>
-          <prop actor="props/structures/decals/gravel_savanna_3v3.xml" attachpoint="root"/>
-          <prop actor="particle/sparkle_goldmine.xml" attachpoint="root"/>
-        </props>
-      </variant>
+      <props>
+        <prop actor="props/structures/decals/gravel_savanna_3v3.xml" attachpoint="root"/>
+        <prop actor="particle/sparkle_goldmine.xml" attachpoint="root"/>
+      </props>
       <textures>
         <texture file="gaia/metal_round_col_india.png" name="baseTex"/>
         <texture file="gaia/stonemine_round_spec.png" name="specTex"/>