iteritems() was dropped in recent Python3 releases and items() is compatible
with Python 2.7.

- skip_verify: {{ true if package.verify else false }}
will be true when package:verify is set to true
And that confuses.

"skip verify" means "skip any verify process" and package should
not be verified during installation

Currently, for disabling verification we use:
linux:
  system:
    package:
      netapp-offload-tool:
        verify: true

And anyone who is reading reclass model can be easily perplexed.
Patchset fixes that issue.

Change-Id: I38d60ff3dbe651e14898c4937fc7dddad36204be

* Allow to install package without specifying any version

* Group packages to install/remove when possible for better performance

"names" makes a separate call to the package management frontend to
install each package, whereas "pkgs" makes just a single call so that it
improves performance.