The backdoor payload is interesting. In response to a :) smiley face in the FTP username, a TCP callback shell is attempted. There is no obfuscation. More interestingly, there's no attempt to broadcast any notification of installation of the bad package. So it's unclear how victims would be identified; and also pretty much guaranteed that any major redistributor would notice the badness. Therefore, perhaps someone was just having some lulz instead of seriously trying to cause trouble.