Propagate OpenSsl errors.
Propagate OpenSsl errors.

We lift OpenSsl errors to IoErrors, conditionally losing some information.

Without a better error abstraction, this is the best we can do without
specializing Connecter to OpenSsl.

Fixes #137

servo/rust-http,Shraddha512/rust-http,Shraddha512/rust-http,chris-morgan/rust-http,Shraddha512/rust-http,Shraddha512/rust-http,chris-morgan/rust-http,servo/rust-http,Shraddha512/rust-http,chris-morgan/rust-http,servo/rust-http,chris-morgan/rust-http,servo/rust-http