r25891: Test that we get the correct return value when we attempt to reference

r25891: Test that we get the correct return value when we attempt to reference

invalid entries with a linked attribute.

Make Samba4 pass that test, by fixing a silly bug in the
linked_attributes module.  (By passing down the 'original' request
structure, tdb would override our handle, and therefore we would never
be called for the 'wait', which collects the errors).

Fix up the provision templates to handle the newly required
referential integrity.

Andrew Bartlett
(This used to be commit 0377d85bbdcb2c4f110b0519005f0d1d10bc0c0b)