fixed another dead assignment found by clang-analyzer in test_dtls_handshake()
fixed another dead assignment found by clang-analyzer in test_dtls_handshake()

randombit/botan,webmaster128/botan,Rohde-Schwarz-Cybersecurity/botan,Rohde-Schwarz-Cybersecurity/botan,randombit/botan,webmaster128/botan,randombit/botan,Rohde-Schwarz-Cybersecurity/botan,randombit/botan,Rohde-Schwarz-Cybersecurity/botan,webmaster128/botan,webmaster128/botan,Rohde-Schwarz-Cybersecurity/botan,Rohde-Schwarz-Cybersecurity/botan,webmaster128/botan,randombit/botan