[REM3-192] Make the underlying SSLSession available from the Connection if one is available.

One more branch requiring this change.

https://issues.jboss.org/browse/REM3-192 Version 3.3.4.Final is in fix versions list, it seems that this fix missed in 3.3 branch. Also, external tracker issue of https://bugzilla.redhat.com/show_bug.cgi?id=1123505 (6.3.x) depends on it.