Christian Cöster

Not sure if this is a separate issue, but I'm getting: `SSL_CTX_set_cipher_list: invalid command` when trying to use tls. It seems like the cipher string https://github.com/graylog-labs/gelf-rb/blob/eb2d31cdc4b37c316de880122279bcac52a08ba2/lib/gelf/transport/tcp_tls.rb#L91 should be: ``` "TLSv1.2:TLSv1.1:TLSv1:!aNULL:!eNULL:!LOW:!3DES:!MD5:!EXP:!PSK:!DSS:!RC4:!SEED:!ECDSA:!ADH:!IDEA:!3DES"...

I made a PR for this.