Add sharetab to joyent zones

*** 49,58 ****
--- 49,59 ----
              opt="ro,nodevices" type="lofs" />
          <global_mount special="%R/local" directory="/usr/local"
              opt="nodevices" type="lofs" />
          <global_mount special="%R/ccs" directory="/usr/ccs"
              opt="nodevices" type="lofs" />
+         <mount special="sharefs" directory="/etc/dfs/sharetab" type="sharefs" />
  
          <!-- Local filesystems to mount when booting the zone -->
          <mount special="/proc" directory="/proc" type="proc" />
          <mount special="ctfs" directory="/system/contract" type="ctfs" />
          <mount special="mnttab" directory="/etc/mnttab" type="mntfs" />