6781 zpool man page needs updated to remove duplicate entry of "cannot be" where it discusses cache devices
Reviewed by: Toomas Soome <tsoome@me.com>
Reviewed by: Robert Mustacchi <rm@joyent.com>

*** 21,31 ****
  .\"
  .\" Copyright (c) 2007, Sun Microsystems, Inc. All Rights Reserved.
  .\" Copyright (c) 2013 by Delphix. All rights reserved.
  .\" Copyright 2016 Nexenta Systems, Inc.
  .\"
! .Dd February 15, 2016
  .Dt ZPOOL 1M
  .Os
  .Sh NAME
  .Nm zpool
  .Nd configure ZFS storage pools
--- 21,31 ----
  .\"
  .\" Copyright (c) 2007, Sun Microsystems, Inc. All Rights Reserved.
  .\" Copyright (c) 2013 by Delphix. All rights reserved.
  .\" Copyright 2016 Nexenta Systems, Inc.
  .\"
! .Dd March 25, 2016
  .Dt ZPOOL 1M
  .Os
  .Sh NAME
  .Nm zpool
  .Nd configure ZFS storage pools
*** 233,244 ****
  raidz vdev types are not supported for the intent log. For more information,
  see the
  .Sx Intent Log
  section.
  .It Sy cache
! A device used to cache storage pool data. A cache device cannot be cannot be
! configured as a mirror or raidz group. For more information, see the
  .Sx Cache Devices
  section.
  .El
  .Pp
  Virtual devices cannot be nested, so a mirror or raidz virtual device can only
--- 233,244 ----
  raidz vdev types are not supported for the intent log. For more information,
  see the
  .Sx Intent Log
  section.
  .It Sy cache
! A device used to cache storage pool data. A cache device cannot be configured
! as a mirror or raidz group. For more information, see the
  .Sx Cache Devices
  section.
  .El
  .Pp
  Virtual devices cannot be nested, so a mirror or raidz virtual device can only