Properly set up local transport data dirs after an initialize operation

We were properly setting up the underlying storage at boot time, but
*not* doing so after an "initialize" operation, i.e. after wiping all
of the data upon request.  The effect was that after an init operation
while using the local transport (e.g. if you disabled backup and then
reenabled it with the local transport as your active one), full-data
backup operations wouldn't work until after the next reboot.

(Resubmit, with fixes, of earlier revert.)

Change-Id: I745cb49b5155119d63cff6fffad5230687faca71