Fix buffer overflow in SSL_get_shared_ciphers() function.

(CVE-2006-3738) [Tavis Ormandy and Will Drewry, Google Security Team]

Fix SSL client code which could crash if connecting to a
 malicious SSLv2 server.  (CVE-2006-4343)
[Tavis Ormandy and Will Drewry, Google Security Team]