Fix Bounding Box on NiAVObject for legacy types

The type was actually Bounding Volume, with the "unknown int" being the bound type.  This compound already existed in the XML for other blocks.

nif.xml

@@ -1720,14 +1720,6 @@
         <add name="Scale" type="float" default="1.0">Scaling part (only uniform scaling is supported).</add>
     </compound>
 
-    <compound name="BoundingBox">
-        Bounding box.
-        <add name="Unknown Int" type="uint" default="1">Usually 1.</add>
-        <add name="Translation" type="Vector3">Translation vector.</add>
-        <add name="Rotation" type="Matrix33">Rotation matrix.</add>
-        <add name="Radius" type="Vector3">Radius, per direction.</add>
-    </compound>
-
 	<bitflags name="FurnitureEntryPoints" storage="ushort">
 		Bethesda Animation. Furniture entry points. It specifies the direction(s) from where the actor is able to enter (and leave) the position.
 		<option value="0" name="Front">front entry point</option>
@@ -2764,8 +2756,8 @@
         <add name="Properties" type="Ref" template="NiProperty" arr1="Num Properties" vercond="(User Version 2 &lt;= 34)">All rendering properties attached to this object.</add>
         <add name="Unknown 1" type="uint" arr1="4" ver2="2.3">Always 2,0,2,0.</add>
         <add name="Unknown 2" type="byte" ver2="2.3">0 or 1.</add>
-        <add name="Has Bounding Box" type="bool" ver1="3.0" ver2="4.2.2.0" />
-        <add name="Bounding Box" type="BoundingBox" cond="Has Bounding Box" ver1="3.0" ver2="4.2.2.0" />
+        <add name="Has Bounding Volume" type="bool" ver1="3.0" ver2="4.2.2.0" />
+        <add name="Bounding Volume" type="BoundingVolume" cond="Has Bounding Volume" ver1="3.0" ver2="4.2.2.0" />
         <add name="Collision Object" type="Ref" template="NiCollisionObject" ver1="10.0.1.0" />
     </niobject>