DO NOT MERGE Fix media scanner uri handling.

If a file was originally considered a video file (because it had
a .mp4 extension, for example), but was then discovered to have
only an audio track, it would update the type, but not the URI
for insertion into the media provider.

Change-Id: I25652a031b98d2ec2433263dd6f344ba90d2d112
Signed-off-by: Mike Lockwood <lockwood@android.com>