This allows address interpolations to work correctly when flatnode storage
is used for node coordinates.
To fix interpolations in an existing database, follow these steps:
* invalidate all interpolations (in psql):
`UPDATE placex SET indexed_status=2 WHERE rank_search = 28`
* disable updates:
./utils/setup.php --create-functions --create-partition-functions
* reindex the whole lot:
./utils/update.php --index --index-instances <number of your cpus>
* enable updates again:
./utils/setup.php --create-functions --enable-diff-updates --create-partition-functions
