Fixed the unit tests using SQLite do not check foreign keys.

Fixed the unit tests using SQLite do not check foreign keys.

The foreign key constraints will be enabled for each SQLite
database connection.

By default the foreign key constraints are disabled in SQLite,
so some test cases failed after enabling the foreign key
constraints for unit tests. This fixings also fixed the failed
test cases because of the foreign key enforcement.

Fixes: bug #1021023
Change-Id: I89f0cbbd75bb685b50dfe6628116fa971c5e78cb