Clarify IPS package versioning format requirements

A note about Solaris 11.1 versioning format:

  $ pkg list -v --no-refresh zsh
  FMRI                                                                         IFO
  pkg://solaris/shell/zsh@4.3.17,5.11-0.175.1.0.0.24.0:20120904T174236Z        i--
  name--------- |<----->| |/________________________\|
  version---------------- |\                        /|

Notice that the publisher and timestamp aren't used. And that the package
version then must have the commas replaced by underscores.

Thus,

    4.3.17,5.11-0.175.1.0.0.24.0

Becomes:

    4.3.17_5.11-0.175.1.0.0.24.0

Therefore, a properly formatted package promise looks like this:

   "shell/zsh"
     package_policy  => "addupdate",
     package_method  => ips,
     package_select  => ">=",
     package_version => "4.3.17_5.11-0.175.1.0.0.24.0";
Merge pull request #475 from bahamat/master

cfengine_stdlib.cf: Clarify IPS package versioning format requirements