1. Encapsulate rspec2genilib in a library function.

2. Add a "check" option UpdateDiskImage() to see if any changes are
   actually going to be made so that we do not create a new version of a
   profile that is identical to the previous version.

3. Do not ever create a new version of a script based profile since we
   can never change the script (after a disk snapshot). Unless it is a
   portal converted script, we can do that by changing the rspec and
   then generating a new script.