Illumos #2703: add mechanism to report ZFS send progress

Reviewed by: Matt Ahrens <matt@delphix.com>
Reviewed by: Robert Mustacchi <rm@joyent.com>
Reviewed by: Richard Lowe <richlowe@richlowe.net>
Approved by: Eric Schrock <Eric.Schrock@delphix.com>

References:
  https://www.illumos.org/issues/2703

Ported by: Martin Matuska <martin@matuska.org>
Signed-off-by: Brian Behlendorf <behlendorf1@llnl.gov>

cmd/zfs/zfs_main.c

@@ -23,6 +23,7 @@
  * Copyright (c) 2005, 2010, Oracle and/or its affiliates. All rights reserved.
  * Copyright 2012 Nexenta Systems, Inc. All rights reserved.
  * Copyright (c) 2012 by Delphix. All rights reserved.
+ * Copyright (c) 2012, Joyent, Inc. All rights reserved.
  */
 
 #include <assert.h>
@@ -3551,6 +3552,7 @@ zfs_do_send(int argc, char **argv)
 			if (flags.verbose)
 				extraverbose = B_TRUE;
 			flags.verbose = B_TRUE;
+			flags.progress = B_TRUE;
 			break;
 		case 'D':
 			flags.dedup = B_TRUE;