It sure doesn't. I tried this method and the autocomplete is still broken. I tried everything. I added a contact with the wrong email address. It had an extra s in the address. I removed the contact, emptied the trash, re-added the contact, and tried again and the wrong address is still in the autocomplete with the same wrong email address. Someone pointed me to:
Bug 40081 – Unable to get rid of emailed contact
This doesn't seem to have any resolution though. It is a pretty horrible bug. If anybody has figured out a way to fix this please let me know.