Use the our platform_family helper

Signed-off-by: Tim Smith <tsmith@chef.io>

recipes/default.rb

@@ -18,7 +18,7 @@
 # See the License for the specific language governing permissions and
 # limitations under the License.
 #
-unless node['platform_family'] == 'windows'
+unless platform_family?('windows')
   return "Chocolatey install not supported on #{node['platform_family']}"
 end