Bugfix: Handling of item locations from old feeds

IDFeed v1.1 (EDK 4.0.7.0 and below) returns inventory flag 0 for fitted
items, and an empty string as edkapi version. IDfeed v1.2 (EDK 4.0.8.0 and
above) will now check for an empty or lesser IDFeed version and assign
zero-value flags on incoming items to their appropriate slot
Bugfix: Set DBUpdate config value during install

Removed DBUpdate value from config.data as it was redundant. During
install the value for DBUpdate will be taken from constants.php and set
correctly to the latest version.