Changing the user name for a CUser instance is a really, really bad idea. There
are lots of paths that depend on the user name and only few of them are fixed up
when the user name changes.
This fixes a problem where admin's "CloneUser from to" caused problems with
modules, because all modules where loaded under the old user name and thus they
read/write NV data from the wrong directory in ~/.znc/users.
Thanks to un1matr1x for reporting this.
Signed-off-by: Uli Schlachter <psychon@znc.in>