start_new_disc: remove /dists/local commodity symlink

When local packages are enabled (LOCAL=1), various things happen in the
target /dists directory. One of them is the creation of a /dists/local
symlink, pointing to (/dists/)<CODENAME>. This leads to a very confusing
situation, where “local” is initially about a component, but effectively
ends up looking like a distribution.

It is theoretically possible that cleaning this up might require some
follow-up fixes in other tools, but even that would be better than
keeping bear traps around.

tools/start_new_disc

@@ -134,12 +134,6 @@ if [ "$BACKPORTS"x != ""x ] ; then
     fi
 fi
 
-# Commodity link for tools which want local in dists/local/local ...
-if [ -n "$LOCAL" ]
-then
-    ln -sf $CODENAME $CDDIR/dists/local
-fi
-
 if [ ! -d $CDDIR/.disk ] ; then
     mkdir $CDDIR/.disk
 fi