Remove CoreInfo from the ClientRegistered handshake message

Remove CoreInfo from the ClientRegistered handshake message

This string was only used by pre-0.5 clients, and even then only
for displaying information on the connection dialog during the
handshake phase, so it is safe to remove. This prevents the core
from leaking information about itself before a successful login.

(cherry picked from commit 3856cfd6126cdea97c91a22be7ded92ccc0a3577)