tls: emit errors happening before handshake finish

This fixes a race condition introduced in 80342f64.
`socket.destroy(err)` only emits the passed error when
`socket._writableState.errorEmitted === false`, `ssl.onerror`
sets `errorEmitted = true` just before calling
`socket.destroy()`.

See: https://github.com/nodejs/io.js/issues/1119
See: https://github.com/nodejs/io.js/issues/1711
PR-URL: https://github.com/nodejs/io.js/pull/1769


Reviewed-By: Fedor Indutny <fedor@indutny.com>