Use BufferedIO#write instead of #writeline
Use BufferedIO#write instead of #writeline

writeline already appends \r\n, which resulted in us sending \r\n\r\n.
We could've stopped appending \r\n, but there is no guarantee that
writeline won't change to \n at some point.

Thanks to Zach Wily for reporting this issue.

brpeterman/cinch,cinchrb/cinch,rpepe/cinch