Remove duplicated test

spec/models/repository_spec.rb

@@ -264,12 +264,6 @@ describe Repository do
         expect_to_raise_storage_error { broken_repository.find_commits_by_message('s') }
       end
     end
-
-    describe 'when storage is broken', :broken_storage do
-      it 'should raise a storage error' do
-        expect_to_raise_storage_error { broken_repository.find_commits_by_message('s') }
-      end
-    end
   end
 
   describe '#blob_at' do