Tab autocomplete causes disconnect from server

In SMP you will be kicked from a server if the autocomplete suggestion list is longer than 100 characters.

Steps to reproduce:
1) Start a 13w21a server and join it
2) Become opped
3) type into the chat "/" then press tab

Result:
You are disconnected with the message "Internal exception: java.io.IOException: Received string length longer than maximum allowed (310 > 100)"