AST-2014-011: Fix POODLE security issues

AST-2014-011: Fix POODLE security issues

There are two aspects to the vulnerability:
(1) res_jabber/res_xmpp use SSLv3 only. This patch updates the module to use
    TLSv1+. At this time, it does not refactor res_jabber/res_xmpp to use the
    TCP/TLS core, which should be done as an improvement at a latter date.
(2) The TCP/TLS core, when tlsclientmethod/sslclientmethod is left unspecified,
    will default to the OpenSSL SSLv23_method. This method allows for all
    encryption methods, including SSLv2/SSLv3. A MITM can exploit this by
    forcing a fallback to SSLv3, which leaves the server vulnerable to POODLE.
    This patch adds WARNINGS if a user uses SSLv2/SSLv3 in their configuration,
    and explicitly disables SSLv2/SSLv3 if using SSLv23_method.

For TLS clients, Asterisk will default to TLSv1+ and WARN if SSLv2 or SSLv3 is
explicitly chosen. For TLS servers, Asterisk will no longer support SSLv2 or
SSLv3.

Much thanks to abelbeck for reporting the vulnerability and providing a patch
for the res_jabber/res_xmpp modules.

Review: https://reviewboard.asterisk.org/r/4096/

ASTERISK-24425 #close
Reported by: abelbeck
Tested by: abelbeck, opsmonitor, gtjoseph
patches:
  asterisk-1.8-jabber-tls.patch uploaded by abelbeck (License 5903)
  asterisk-11-jabber-xmpp-tls.patch uploaded by abelbeck (License 5903)
  AST-2014-011-1.8.diff uploaded by mjordan (License 6283)
  AST-2014-011-11.diff uploaded by mjordan (License 6283)

git-svn-id: https://origsvn.digium.com/svn/asterisk/branches/12@425987 65c4cc65-6c06-0410-ace0-fbb531ad65f3