There was a rare, tricky race condition in the setup, where a pull could
get started, find the blocks from the file we injected in
updateLocalsFromScanning, copy them into a temp file, then fail the pull
because the file was already in place. Then later, after the revert,
another pull would start, find the temp file and reuse it, making it so
needed=0 instead of the expected needed>0 the test checks for.
This avoids all that by setting the local index data prior to getting it
from the "remote" device, thus avoiding the initial pull and temp file
creation etc.
Signed-off-by: Jakob Borg <jakob@kastelo.net>