Move SSL socket to folly

Move SSL socket to folly

Summary: One of the last thrift -> folly moves.  The only change was the exception types - there are small wrapper classes in thrift/lib/cpp/async left to convert from AsyncSocketException to TTransportException.

Test Plan: run unit tests

Reviewed By: dcsommer@fb.com

Subscribers: jdperlow, trunkagent, doug, bmatheny, ssl-diffs@, njormrod, mshneer, folly-diffs@, fugalh, jsedgwick, andrewcox, alandau

FB internal diff: D1632425

Signature: t1:1632425:1414526483:339ae107bacb073bdd8cf0942fd0f6b70990feb4