ZCO + roaming users + shared mailboxes

The ZCO crashes when dealing with roaming users who access shared mailboxes.

User logs into machine A:
- user starts Outlook, and Outlook.zdb is created and updated
- user subscribes to a shared mailbox, and Outlook1.zdb is created and updated

User then logs into machine B:
- user starts Outlook, ZCO cannot find Outlook.zdb, so creates it and syncs user's mail
- ZCO cannot find Outlook1.zdb, but instead of creating it, crashes

To repeat:
Set up a user in Outlook using the ZCO as normal.
Have them subscribe to a shared mailbox.
Exit Outlook, go into %APPDATA%\Local\Microsoft\Outlook, and delete the Outlook1.zdb
Start Outlook again, it will crash.

Tested with the latest ZCO (7.1.2), on Windows XP and Windows 7 64-bit, with Office 2003 and Office 2010.

Debug logs available on request.

http://bugzilla.zimbra.com/show_bug.cgi?id=64419