remove the ls=ls -gCF alias: we already have an alias for ls (-CF),

remove the ls=ls -gCF alias: we already have an alias for ls (-CF),
and now that the behaviour of -g has changed to be more in line
with posix, we get group ID by default anyway;

kick started by PR 5784 from Jacek Masiulaniec;
discussed with otto and sobrado;
ok deraadt millert