10084 fop_open() doesn't need to check for a NULL vnode

*** 19,29 ****
   * CDDL HEADER END
   */
  
  /*
   * Copyright (c) 1988, 2010, Oracle and/or its affiliates. All rights reserved.
!  * Copyright 2017, Joyent, Inc.
   * Copyright 2016 Nexenta Systems, Inc.  All rights reserved.
   * Copyright (c) 2011, 2017 by Delphix. All rights reserved.
   */
  
  /*      Copyright (c) 1983, 1984, 1985, 1986, 1987, 1988, 1989 AT&T     */
--- 19,29 ----
   * CDDL HEADER END
   */
  
  /*
   * Copyright (c) 1988, 2010, Oracle and/or its affiliates. All rights reserved.
!  * Copyright (c) 2018, Joyent, Inc.
   * Copyright 2016 Nexenta Systems, Inc.  All rights reserved.
   * Copyright (c) 2011, 2017 by Delphix. All rights reserved.
   */
  
  /*      Copyright (c) 1983, 1984, 1985, 1986, 1987, 1988, 1989 AT&T     */
*** 3366,3376 ****
                   * copy over the path, do so here, rather than special
                   * casing each filesystem. Adjust the vnode counts to
                   * reflect the vnode switch.
                   */
                  VOPSTATS_UPDATE(*vpp, open);
!                 if (*vpp != vp && *vpp != NULL) {
                          vn_copypath(vp, *vpp);
                          if (((*vpp)->v_type == VREG) && (mode & FREAD))
                                  atomic_inc_32(&(*vpp)->v_rdcnt);
                          if ((vp->v_type == VREG) && (mode & FREAD))
                                  atomic_dec_32(&vp->v_rdcnt);
--- 3366,3376 ----
                   * copy over the path, do so here, rather than special
                   * casing each filesystem. Adjust the vnode counts to
                   * reflect the vnode switch.
                   */
                  VOPSTATS_UPDATE(*vpp, open);
!                 if (*vpp != vp) {
                          vn_copypath(vp, *vpp);
                          if (((*vpp)->v_type == VREG) && (mode & FREAD))
                                  atomic_inc_32(&(*vpp)->v_rdcnt);
                          if ((vp->v_type == VREG) && (mode & FREAD))
                                  atomic_dec_32(&vp->v_rdcnt);