Fix incorrect blocked LOS-calculation on certain locations (by Lynx3d)

--HG--
branch : trunk

src/server/collision/Models/ModelInstance.cpp

@@ -57,8 +57,11 @@ namespace VMAP
         Ray modRay(p, iInvRot * pRay.direction());
         float distance = pMaxDist * iInvScale;
         bool hit = iModel->IntersectRay(modRay, distance, pStopAtFirstHit);
-        distance *= iScale;
-        pMaxDist = distance;
+        if(hit)
+        {
+            distance *= iScale;
+            pMaxDist = distance;
+        }
         return hit;
     }