[FIX] data dir when home is not a directory

Use site data dir instead of user data dir when user's home is not a directory.
Like system users created with /dev/null as home.

Stricter than before.
Merge pull request #1343 from vice/master

[FIX] data dir when home is not a directory
[IMP] [DATA] product: added default product.product data (Miscellaneous), consumable and available for the point of sale.