Today I locked myself out by doing something like you did.
I can not access my server anymore, and as it's a test server in Alphen a/d Rijn (grafix) I need to go there tomorrow and rewrite the file interfaces (add the correct info).
I'm using eth6 an eth7 in it, and ISPconfig changed it to eth0 and 0:0
(for some reason eth0 till eth5 do not work on my system).
Long car drive tomorrow :-(
Never execute code written on a Friday or a Monday.