Fix error in attribute copying to rlm_perl

Introduced in commit c225c615760d4c907640ebd249f860d5ab3258dd. It copied the RAD_REPLY hash twice, which had the side effects that some keys dropped out.
Merge pull request #742 from qnet-herwin/rlm_perl_v3.0.x

Fix error in attribute copying to rlm_perl