Keep 'show log' on screen until user dismisses it

Also increase log output to 24 lines

Change-Id: I11381e347c2238f2058ea97f9143476ec3a80cf6
dedupe: backup & restore selinux contexts.

- patch set 2: remove the comment line, adjust freecon.

Change-Id: Ib691146f5e4d33014aac2b540aefc06657818eb4
create /data/media directory after internal storage is wiped

This will prevent denial to read/write from internal storage under some circumstances

Change-Id: I10ee3dcdbe4ce7063f534f59a5e09c2ec33c1b7a
format non vold extra storage to ext4 when no selinux context is defined

Change-Id: I810d071c53d570ff0c53ea3a69e4225b4df81db1