Allow for older versions of stomp.py

- Make the ssl module optional to allow for Python < 2.6 if an SSL
  connection isn't needed.
- Change the code to try and set ssl_version in the stomp.py Connection
  but fall back to overriding the value of ssl.PROTOCOL_SSLv3 in the stomp
  namespace. This allows for versions of stomp.py <= 3.0.3.
Revert "Add python-ssl as dependency on el5 (i.e. SL5)"

This reverts commit a75717229139ae2e7f9539bf2b05b1935c64b35d.

- Revert this commit as the use of SSL should be optional in some
  contexts.
Update version and changelogs for rc3