Try to remove assumption that zone's root vnode is marked VROOT

@@ -956,11 +956,11 @@
                 /*
                  * If dotdotting at the root of a filesystem, then
                  * need to traverse back to the mounted-on filesystem
                  * and do the dotdot lookup there.
                  */
-                if (cs->vp->v_flag & VROOT) {
+                if ((cs->vp->v_flag & VROOT) || VN_IS_CURZONEROOT(cs->vp)) {
 
                         /*
                          * If at the system root, then can
                          * go up no further.
                          */

@@ -2703,11 +2703,11 @@
                 /*
                  * If dotdotting at the root of a filesystem, then
                  * need to traverse back to the mounted-on filesystem
                  * and do the dotdot lookup there.
                  */
-                if (cs->vp->v_flag & VROOT) {
+                if ((cs->vp->v_flag & VROOT) || VN_IS_CURZONEROOT(cs->vp)) {
 
                         /*
                          * If at the system root, then can
                          * go up no further.
                          */