OS-5148 ftruncate at offset should emit proper events
Reviewed by: Bryan Cantrill <bryan@joyent.com>
Reviewed by: Jerry Jelinek <jerry.jelinek@joyent.com>

*** 779,791 ****
                  error = pc_truncate(pcp, (uint_t)vap->va_size);
  
                  if (error)
                          goto out;
  
!                 if (vap->va_size == 0)
                          vnevent_truncate(vp, ct);
          }
          /*
           * Change file modified times.
           */
          if (mask & (AT_MTIME | AT_CTIME)) {
                  /*
--- 779,794 ----
                  error = pc_truncate(pcp, (uint_t)vap->va_size);
  
                  if (error)
                          goto out;
  
!                 if (vap->va_size == 0) {
                          vnevent_truncate(vp, ct);
+                 } else {
+                         vnevent_resize(vp, ct);
                  }
+         }
          /*
           * Change file modified times.
           */
          if (mask & (AT_MTIME | AT_CTIME)) {
                  /*