3006 VERIFY[S,U,P] and ASSERT[S,U,P] frequently check if first argument is zero

*** 18,27 ****
--- 18,28 ----
   *
   * CDDL HEADER END
   */
  /*
   * Copyright (c) 2009, 2010, Oracle and/or its affiliates. All rights reserved.
+  * Copyright (c) 2012 by Delphix. All rights reserved.
   */
  
  /*
   * The System Duty Cycle (SDC) scheduling class
   * --------------------------------------------
*** 1303,1316 ****
  
          sdp.sdp_minpri = sysdc_minpri;
          sdp.sdp_maxpri = sysdc_maxpri;
          sdp.sdp_DC = MAX(MIN(dc, sysdc_maxDC), sysdc_minDC);
  
!         VERIFY3U(CL_ALLOC(&buf, sysdccid, KM_SLEEP), ==, 0);
  
          ASSERT(t->t_lwp != NULL);
          ASSERT(t->t_cid == syscid);
          ASSERT(t->t_cldata == NULL);
!         VERIFY3U(CL_CANEXIT(t, NULL), ==, 0);
!         VERIFY3U(CL_ENTERCLASS(t, sysdccid, &sdp, kcred, buf), ==, 0);
          CL_EXITCLASS(syscid, NULL);
  }
--- 1304,1317 ----
  
          sdp.sdp_minpri = sysdc_minpri;
          sdp.sdp_maxpri = sysdc_maxpri;
          sdp.sdp_DC = MAX(MIN(dc, sysdc_maxDC), sysdc_minDC);
  
!         VERIFY0(CL_ALLOC(&buf, sysdccid, KM_SLEEP));
  
          ASSERT(t->t_lwp != NULL);
          ASSERT(t->t_cid == syscid);
          ASSERT(t->t_cldata == NULL);
!         VERIFY0(CL_CANEXIT(t, NULL));
!         VERIFY0(CL_ENTERCLASS(t, sysdccid, &sdp, kcred, buf));
          CL_EXITCLASS(syscid, NULL);
  }