libstore: Do not normalize daemon -> unix://, local -> local://

This is relied upon (specifically the `local` store) by existing
tooling [1] and we broke this in 3e7879e6df (which
was first released in 2.31).

To lessen the scope of the breakage we should not normalize "auto" references
and explicitly specified references like "local" or "daemon". It also makes
sense to canonicalize local://,daemon:// to be more compatible with prior
behavior.

[1]: 05e1b3cba2/lib/NOM/Builds.hs (L60-L64)

(cherry picked from commit 3513ab13dc)

src/libstore/store-reference.cc

@@ -25,6 +25,8 @@ std::string StoreReference::render(bool withParams) const
     std::visit(
         overloaded{
             [&](const StoreReference::Auto &) { res = "auto"; },
+            [&](const StoreReference::Daemon &) { res = "daemon"; },
+            [&](const StoreReference::Local &) { res = "local"; },
             [&](const StoreReference::Specified & g) {
                 res = g.scheme;
                 res += "://";
@@ -68,21 +70,17 @@ StoreReference StoreReference::parse(const std::string & uri, const StoreReferen
                 .params = std::move(params),
             };
         } else if (baseURI == "daemon") {
+            if (params.empty())
+                return {.variant = Daemon{}};
             return {
-                .variant =
-                    Specified{
-                        .scheme = "unix",
-                        .authority = "",
-                    },
+                .variant = Specified{.scheme = "unix", .authority = ""},
                 .params = std::move(params),
             };
         } else if (baseURI == "local") {
+            if (params.empty())
+                return {.variant = Local{}};
             return {
-                .variant =
-                    Specified{
-                        .scheme = "local",
-                        .authority = "",
-                    },
+                .variant = Specified{.scheme = "local", .authority = ""},
                 .params = std::move(params),
             };
         } else if (isNonUriPath(baseURI)) {