Handle DTLS hello request without recursion

Fix CVE-2014-0221

Unnecessary recursion when receiving a DTLS hello request can be used to
crash a DTLS client. Fixed by handling DTLS hello request without recursion.

http://git.openssl.org/gitweb/?p=openssl.git;a=commit;h=b4322e1de8be66ff230e26999b766ca1a42f9476