Add "default_normal" support to vold.

This new flag isolates each user on a multi-user device for security
reasons.

Test: cts-tradefed run commandAndExit cts-dev -m CtsAppSecurityHostTestCases -t android.appsecurity.cts.ExternalStorageHostTest#testSecondaryUsersInaccessible
Bug: 64672411
Change-Id: I3db8dde597a7715ca680779ac57957fb12a92f8e
1 file changed