Resolve tls issues

I recommend these commits be reverted for the moment.

I can confirm they cause a problem with imap.secureserver.net (godaddy).  I suspect its the combination of the commits that is causing problems.  One connection may use TLS 1.2.  The session is saved & reused for the next connection, but the next server only talks TLS 1.0 and complains of a wrong protocol version.  Either commit by itself does not seem to cause the problem.

Ultimately, I think we should probably turn these into optional settings.  Thunderbird uses TLS 1.0, so that behavior should probably remain the default.  They also use session caching, but I've seen where they are considering making it optional for those concerned about certain privacy issues.