Added CVE-2012-2686

Added Module for a DoS issue in OpenSSL (pre 1.0.1d). Can be exploited
with services that use TLS >= 1.1 and AES-NI. Because of improper
length computation, an integer underflow occurs leading to a
segmentation fault. This module brute-forces serveral encrypted
messages - when the decrypted message coincidentally specifies a
certain value for the size, the integer underflow occurs. Though this
could be accomplished more effectively (e.g. implementing or
maninpulating and TLS implementation), this module still does what it
should do.
Beautified OpenSSL-AESNI module

Modifed the CVE-2012-2686 module to follow
suggestions by @jvazquez-r7:
* Added description for all fields in the
  SSL packets
* MAX_TRIES now required
* use get_once instead of timeout
Merge branch 'module-cve-2012-2686' of https://github.com/ettisan/metasploit-framework into ettisan-module-cve-2012-2686
cleanup for openssl_aesni