mount preload partition at the end

preload is a useless partition and can be fotmatted as swap or other filesystem
different from ext4. In this case 'mount_all' will fail, leaving data unmounted

Change-Id: I37b81680f0e37590e6cd5142fa1950cd5ba90960
Merge remote-tracking branch 'upstream/cm-10.1' into cm-10.1