glibc: remove installLocales argument

Since we now install a sane default this should be no longer necessary.
If it is still needed, it should be easy enough to do this in an overlay.

pkgs/development/libraries/glibc/locales.nix

@@ -13,8 +13,6 @@
 callPackage ./common.nix { inherit stdenv; } {
   name = "glibc-locales";
 
-  installLocales = true;
-
   builder = ./locales-builder.sh;
 
   outputs = [ "out" ];