cvsserver: Don't send mixed messages to clients

cvsserver: Don't send mixed messages to clients

After we send I HATE YOU we should probably exit and not happily
continue with I LOVE YOU and further communication.

Most clients will probably just exit and ignore everything we
send after the I HATE YOU and it is not a security problem
either because we don't really care about the user name anyway.

But it is still the right thing to do.

[jc: with a minor fixup to its exit code...]

Signed-off-by: Frank Lichtenheld <redacted>
Acked-by: "Martin Langhoff" <redacted>
Signed-off-by: Junio C Hamano <redacted>