OpenZFS 6872 - zfs libraries should not allow uninitialized variables

Porting notes:
- Many changes were already made in ZoL (for ex. in d4ed667).

Authored by: Paul Dagnelie <pcd@delphix.com>
Reviewed by: Dan Kimmel <dan.kimmel@delphix.com>
Reviewed by: George Wilson <george.wilson@delphix.com>
Reviewed by: Prakash Surya <prakash.surya@delphix.com>
Reviewed by: Yuri Pankov <yuri.pankov@nexenta.com>
Approved by: Robert Mustacchi <rm@joyent.com>
Reviewed-by: Brian Behlendorf <behlendorf1@llnl.gov>
Ported-by: George Melikov <mail@gmelikov.ru>

OpenZFS-issue: https://www.illumos.org/issues/6872
OpenZFS-commit: openzfs/openzfs@f83b46b
Closes openzfs#5640

cmd/zpool/zpool_vdev.c

@@ -21,7 +21,7 @@
 
 /*
  * Copyright (c) 2005, 2010, Oracle and/or its affiliates. All rights reserved.
- * Copyright (c) 2013 by Delphix. All rights reserved.
+ * Copyright (c) 2013, 2015 by Delphix. All rights reserved.
  * Copyright (c) 2016 Intel Corporation.
  * Copyright 2016 Igor Kozhukhov <ikozhukhov@gmail.com>.
  */
@@ -787,7 +787,6 @@ get_replication(nvlist_t *nvroot, boolean_t fatal)
 	verify(nvlist_lookup_nvlist_array(nvroot, ZPOOL_CONFIG_CHILDREN,
 	    &top, &toplevels) == 0);
 
-	lastrep.zprl_type = NULL;
 	for (t = 0; t < toplevels; t++) {
 		uint64_t is_log = B_FALSE;