fstab: Run fsck on /persist too.

This partition gets no activity, but it can still get corrupted by
unclean shutdowns; fsck all the things

Change-Id: I60c08b5d3157e582c96f5131fd0195dd591f6fc1
bacon: Move mkbootimg to common repo

Change-Id: Ia1e819de142a5bb86241f8113a99770fbc6fc2a3