ocamlPackages.findlib: don't wait configurePhase to set OCAMLFIND_DESTDIR
ocamlPackages.findlib: don't wait configurePhase to set OCAMLFIND_DESTDIR

this fixes ocamlfind printconf destdir inside nix-shell

fixes #152028

the regression was introduced by
a3ab43d3a45338f845a0f8a12ed34e84c8b79dae which was meant to fix building
ocamlPackages.ocamlbuild with strictDeps. This commit keeps ocamlbuild
building.

NixOS/nixpkgs,NixOS/nixpkgs,NixOS/nixpkgs,NixOS/nixpkgs,NixOS/nixpkgs,NixOS/nixpkgs,NixOS/nixpkgs,NixOS/nixpkgs,NixOS/nixpkgs,NixOS/nixpkgs,NixOS/nixpkgs,NixOS/nixpkgs,NixOS/nixpkgs,NixOS/nixpkgs,NixOS/nixpkgs