Account for race condition with w = 0

Author: estolfo

spec/mongo/operation/write/bulk/bulk_delete_spec.rb

@@ -226,6 +226,7 @@
 
           it 'does not abort after first error' do
             failing_delete.execute(authorized_primary.context)
+            sleep(1)
             expect(authorized_collection.find.count).to eq(1)
           end
         end