Remote: deps: use directory (#120)

`which` is excessive, it depends on TH & `shelly` which depends on a lot of things and also `directory`.

hnix-store-remote/hnix-store-remote.cabal

@@ -87,5 +87,4 @@ test-suite hnix-store-remote-tests
                    , unix
                    , unordered-containers
                    , vector
-                   , which
   default-language: Haskell2010

hnix-store-remote/tests/Derivation.hs

@@ -21,7 +21,7 @@ import qualified Data.Text.Lazy.Builder
 import qualified Data.Vector
 import qualified System.Nix.Derivation
 import qualified System.Nix.StorePath
-import qualified System.Which
+import qualified System.Directory
 
 drvSample :: StorePath -> StorePath -> StorePath -> Derivation StorePath Text
 drvSample builder' buildScript out = Derivation {
@@ -36,7 +36,7 @@ drvSample builder' buildScript out = Derivation {
 
 withBash :: (StorePath -> MonadStore a) -> MonadStore a
 withBash action = do
-  mfp <- liftIO $ System.Which.which "bash"
+  mfp <- liftIO $ System.Directory.findExecutable "bash"
   case mfp of
     Nothing -> error "No bash executable found"
     Just fp -> do

overlay.nix

@@ -8,7 +8,9 @@ pkgs: hlib: helf: huper: {
       "-fio-testsuite"
       {}
     ).overrideAttrs (attrs: {
-        buildInputs = attrs.buildInputs ++ [ pkgs.nix pkgs.which ];
+        buildInputs = attrs.buildInputs ++ [
+          pkgs.nix
+        ];
     });
   #  2020-12-30: NOTE: Remove after switch from cryptohash
   cryptohash-sha512 =