Allow passing options to package resource

The splunkforwarder rpm is relocatable but the cookbook doesn't allow us to set this currently as it doesn't have a reference to the package 'options' attribute.  This adds it per http://docs.opscode.com/resource_package.html.  We are utilizing this functionality in our fork with:

['splunkforwarder']['install_options'] = "--allfiles --relocate /opt=/opt/apps/ms"