re #12611 rb4105 zpool import panic in ddt_zap_count()

*** 19,28 ****
--- 19,29 ----
   * CDDL HEADER END
   */
  
  /*
   * Copyright (c) 2009, 2010, Oracle and/or its affiliates. All rights reserved.
+  * Copyright 2013 Nexenta Systems, Inc.  All rights reserved.
   */
  
  #include <sys/zfs_context.h>
  #include <sys/spa.h>
  #include <sys/zio.h>
*** 132,149 ****
          }
          zap_cursor_fini(&zc);
          return (error);
  }
  
! static uint64_t
! ddt_zap_count(objset_t *os, uint64_t object)
  {
!         uint64_t count = 0;
  
!         VERIFY(zap_count(os, object, &count) == 0);
! 
!         return (count);
  }
  
  const ddt_ops_t ddt_zap_ops = {
          "zap",
          ddt_zap_create,
--- 133,149 ----
          }
          zap_cursor_fini(&zc);
          return (error);
  }
  
! static int
! ddt_zap_count(objset_t *os, uint64_t object, uint64_t *count)
  {
!         int error = zap_count(os, object, count);
!         ASSERT(error == 0);
  
!         return (error);
  }
  
  const ddt_ops_t ddt_zap_ops = {
          "zap",
          ddt_zap_create,