(MCO-489) Disable empty fragments for BEAST attack mitigation

Ruby 2 disables this flag by default (thus enabling empty fragments) for
BEAST attack mitigation. Empty fragments are used when using TLSv1.0
with a CBC mode cipher. For reasons as-yet unclear, ActiveMQ seems to
respond poorly when they are used, and mcollective can't talk to it.

This is problematic combined with the previous patch to disable SSLv2
and SSLv3, because versions of openssl < 1.0.1 (which are still common)
don't support TLSv1.1 or TLSv1.2. This leaves only TLSv1.0 as an
option, with CBC mode ciphers preferred. This causes trouble with
ActiveMQ.

Because BEAST isn't an attack that affects mcollective (it's a
chosen-plaintext attack against browsers), this commit just reenables
the flag to disable empty fragments. This means mcollective will
be able to talk to ActiveMQ on ruby 2.0 with openssl < 1.0.1.
Merge pull request #257 from nicklewis/MCO-489-disable-beast-mitigation

(MCO-489) Disable empty fragments for BEAST attack mitigation