intg: Use different uid range for add_remove tests
    
    Most linux distribution create local users from UID 1000.
    We used similar UID space in sssd but it might caused
    issues in add remove tests becuase sssd in cwrap enviroment
    run in the same PID space. If sssd try to remove user
    with uid 1001 it will fail because the local user with the same UID
    is active and sssd does not remove active users.
    
    Reviewed-by: Petr Cech <pcech@redhat.com>
    (cherry picked from commit e97d9972e8ad05dff1a3b99468ee5728c2c183a8)