Pass an array to function_versioncmp.

function_versioncmp() should take an array containing the two
versions rather than the versions as separate args.  There's a
discussion (and inadequate explanation) of this here:

http://projects.puppetlabs.com/issues/10934

The previous version worked fine, but it threw a ton of warnings
on the puppetmaster like this:

"/usr/lib/ruby/1.8/puppet/parser/functions/versioncmp.rb:30: warning:
multiple values for a block parameter (2 for 1)"

Change-Id: Ied8e6c2871657e876367aff7205c1cb8fbe986f7
Merge "Pass an array to function_versioncmp." into production