Fix default surface resolution U/V mis-match

The resolution for surfaces was 12 for U, 4 for V,
where both should have been set to 4.

Regression in 9a076dd95a

source/blender/blenkernel/intern/curve.c

@@ -215,6 +215,7 @@ void BKE_curve_init(Curve *cu, const short curve_type)
     cu->tb[0].w = cu->tb[0].h = 0.0;
   }
   else if (cu->type == OB_SURF) {
+    cu->resolu = 4;
     cu->resolv = 4;
   }
 }