Reported by Federico Beffa <beffa@ieee.org>
at <https://lists.gnu.org/archive/html/guix-devel/2016-05/msg00928.html>.
* nix/libstore/local-store.cc (LocalStore::querySubstitutablePaths)
(LocalStore::querySubstitutablePathInfos): Return when
'settings.useSubstitutes' is false.
* tests/store.scm ("references/substitutes missing reference info"):
Make sure to return #f on failure.
* tests/store.scm ("substitutable-path-info when substitutes are turned off"):
("substitutable-paths when substitutes are turned off"): New tests.
151afd84dc