Fixed crash related to missing lon/lat in deletions

Previously if when attempting to delete a node osm2pgsql would crash if
the lon/lat was not provided even though this data was not necessary.
It will still crash if you are not trying to delete.
Merge branch 'master' of github.com:mr/osm2pgsql
Merge pull request #131 from mr/master

Fixed crash related to missing lat/lon in deletions