* IMAP/POP rely on sender to set mime type of attachments
* Which doesn't always work, because senders don't always provide it
* Remap using filename extensions, when needed
* This is applied as late as possible - in the MessageView, and in
the content provider getType(). No changes to how we write databases,
and no change to existing attachment rows.
Bug: 2356638
Change-Id: Ie69e3fd12f406aac803583f9d1299a8af4fba010
80ebde2897