Have freebsd port use pkg info if the freebsd version is >= 10000017

The port package provider for FreeBSD was not checking if the freebsd version is version 10. This causes the provider to attempt to use 'pkg_info' instead of 'pkg info'. This PR should fix this bug.
How about moving these to PortsHelper in https://github.com/opscode/chef/blob/master/lib/chef/provider/package/freebsd/base.rb and including in the resource and ports provider? This would also allow the usage of PortsHelper#makefile_variable_value for both.