The cache has no package named 'app-install-data'

[Michael Nelson]

Since 2012-08-01, the import-app-install-data.log shows the import process failing with "The cache has no package named 'app-install-data'" while importing data for natty [1]. The package exists in natty [2], and this was working on the previous day.

If it is a corrupt on-disk cache, we could `rm -rf` the natty cache (it's location will be shown by the setting DISK_APT_CACHE_LOCATION /natty - `manage.py settings disk_apt_cache_location` to get the setting), as this will force the natty cache to be regenerated during the next run. (It should be possible to test the cache on the command line using `apt-cache -p /path/to/ondisk/cache`).

[1] https://pastebin.canonical.com/71507/
[2] http://packages.ubuntu.com/natty/app-install-data