AI: Distro Constructor and a Custom Script

When building your own AI images with distro_const it is useful sometimes to add a custom script to modify the resulting image. This is easily achievable by adding a custom script to the xml manifest provided to distro_cons.

For example, to change the default password for user jack, add the following checkpoint to the xml file, just before pre-pkg-img-mode checkpoint. 

<!--
  Set password to user jack, should match root password
  (if hash contains slashed they need to be backslashed)
-->
      <checkpoint name="lock-jack-account"
         desc="Lock the jack account from login"
         mod_path="solaris_install/distro_const/checkpoints/custom_script"
         checkpoint_class="CustomScript">
         <args>/usr/bin/gsed -i -e 's/jack:.[^:]*:/jack:XXXXXX:/g' 
                             {PKG_IMAGE_PATH}/etc/shadow
         </args>
      </checkpoint>