Yum 300 unfix

As per conversation in https://github.com/sensu/sensu-chef/issues/212, the gpgcheck=true change was short sighted.  Other cookbook's need to comply with yum cookbook v3 before this change can be made.  Until then yum should be pegged at <= 2.4.4 and other cookbooks that already make the move to yum v3 need to not be used, erlang cookbook v1.4.0 for example.