Use repository.shard instead of repository_storage

ee/app/models/group_wiki.rb

@@ -9,7 +9,7 @@ class GroupWiki < Wiki
     super
 
     storage_record = container.group_wiki_repository || container.build_group_wiki_repository
-    storage_record.update!(shard_name: repository_storage, disk_path: storage.disk_path)
+    storage_record.update!(shard_name: repository.shard, disk_path: storage.disk_path)
   end
 
   override :storage

ee/spec/models/group_wiki_spec.rb

@@ -13,7 +13,10 @@ RSpec.describe GroupWiki do
 
     describe '#create_wiki_repository' do
       before do
-        # Don't actually create the repository, because we're using storage shards that don't exist.
+        # Use a custom storage shard value, to make sure we're not falling back to the default.
+        allow(subject).to receive(:repository_storage).and_return('foo')
+
+        # Don't actually create the repository, because the storage shard doesn't exist.
         allow(subject.repository).to receive(:create_if_not_exists)
         allow(subject).to receive(:repository_exists?).and_return(true)
       end
@@ -27,8 +30,6 @@ RSpec.describe GroupWiki do
         end
 
         it 'tracks the storage location' do
-          expect(subject).to receive(:repository_storage).and_return('foo')
-
           subject.create_wiki_repository
 
           expect(wiki_container.group_wiki_repository).to have_attributes(
@@ -44,7 +45,6 @@ RSpec.describe GroupWiki do
         end
 
         it 'updates the storage location' do
-          expect(subject).to receive(:repository_storage).and_return('foo')
           expect(subject.storage).to receive(:disk_path).and_return('fancy/new/path')
 
           subject.create_wiki_repository