Remove backend dependency from fs/hash

fs/object/object.go

@@ -79,7 +79,7 @@ func (memoryFs) String() string { return "memory" }
 func (memoryFs) Precision() time.Duration { return time.Nanosecond }
 
 // Returns the supported hash types of the filesystem
-func (memoryFs) Hashes() hash.Set { return hash.Supported }
+func (memoryFs) Hashes() hash.Set { return hash.Supported() }
 
 // Features returns the optional features of this Fs
 func (memoryFs) Features() *fs.Features { return &fs.Features{} }

fs/object/object_test.go

@@ -53,7 +53,7 @@ func TestMemoryFs(t *testing.T) {
 	assert.Equal(t, "", f.Root())
 	assert.Equal(t, "memory", f.String())
 	assert.Equal(t, time.Nanosecond, f.Precision())
-	assert.Equal(t, hash.Supported, f.Hashes())
+	assert.Equal(t, hash.Supported(), f.Hashes())
 	assert.Equal(t, &fs.Features{}, f.Features())
 
 	entries, err := f.List(context.Background(), "")