Fix a failed assert in the getCell() check during a new game start

apps/openmw/mwworld/worldimp.cpp

@@ -2118,7 +2118,9 @@ namespace MWWorld
 
         pos.z() += heightRatio*2*mPhysics->getRenderingHalfExtents(object).z();
 
-        return isUnderwater(object.getCell(), pos);
+        const CellStore *currCell = object.isInCell() ? object.getCell() : NULL; // currCell == NULL should only happen for player, during initial startup
+
+        return isUnderwater(currCell, pos);
     }
 
     bool World::isUnderwater(const MWWorld::CellStore* cell, const osg::Vec3f &pos) const