Calls mixlib-install even when download_url_override is set

[jaymzh]

If you're on chef 15 and thus have a mixlib-install that doesn't understand the cinc product, and set product_name 'cinc', while also setting download_url_override you'll mixlib-install blowing up because cinc is not a valid product. :/

You can set it to chef - various parts of the upgrade script will blow up with things like:

c:/opscode/chef/embedded/bin/ruby.exe : The term 'c:/opscode/chef/embedded/bin/ruby.exe' is not recognized as the name of a cmdlet, function, script file, or operable program. Check the spelling of the name, or if a path was included,

but the upgrade will be otherwise successful. But we should fix this.

[rmcleod8]

this also happens with chef-client 14 -> cinc, but can confirm setting the product_name value to 'chef' does infact allow the resource to succeed. still working on confirming it actually installing cinc