GTNPC-101: Needed for https://bugzilla.redhat.com/show_bug.cgi?id=908853

Use the original portlet id as available from the provided state instead of the one available from the provided PortletContext so that imported state always refer to a resolvable portlet (which might not happen if the provided PortletContext is that of a clone).

(cherry-picked from 5c8b6fa)