Nest: Fix export of tmpattrs through pipes

Nest: Fix export of tmpattrs through pipes

Pipes copy the original rte with old values, so they require rte to be
exported with stored tmpattrs. Other protocols access stored attributes
using eattr list, so they require rte to be exported with expanded
tmpattrs. This is temporary hack, we plan to remove whoe tmpattr mechanism.

Thanks to Paul Donohue for the bugreport.