Fix exportReferencesGraph when given store subpath

With Nix 2.3, it was possible to pass a subpath of a store path to
exportReferencesGraph:

	with import <nixpkgs> {};

	let
	  hello = writeShellScriptBin "hello" ''
	    echo ${toString builtins.currentTime}
	  '';
	in

	writeClosure [ "${hello}/bin/hello" ]

This regressed with Nix 2.4, with a very confusing error message, that
presumably indicates it was unintentional:

	error: path '/nix/store/3gl7kgjr4pwf03f0x70dgx9ln3bhl7zc-hello/bin/hello' is not in the Nix store

(cherry picked from commit 0774e8ba33c060f56bad3ff696796028249e915a)
Change-Id: I00920fb33077b831a1bb4a1b68d515ba8c3c2a69

0 files changed, 0 insertions, 0 deletions