removeReferencesTo: kill lone hashes

Nix counts any occurrence of a store path's *hash* as a reference, even
without a store directory prefix. The current version only kills
references of the form `/nix/store/<hash>-`, which can fail e.g. for
compressed files.

pkgs/build-support/remove-references-to/remove-references-to.sh

@@ -27,7 +27,7 @@ for i in "$@"; do
 done
 
 for target in "${targets[@]}" ; do
-    sed -i -e "s|@storeDir@/$target-|@storeDir@/eeeeeeeeeeeeeeeeeeeeeeeeeeeeeeee-|g" "${regions[@]}"
+    sed -i -e "s|$target|eeeeeeeeeeeeeeeeeeeeeeeeeeeeeeee|g" "${regions[@]}"
 done
 
 for region in "${regions[@]}"; do