Whitebox server expects deleted > 0

Whitebox servers tests expected deleted == 1.
Behaviour changed no nova side, now DB field
instances.deleted is set to the instance DB ID,
which is an interger > 0.

Fixes: lp/1208267
Change-Id: I659ab17507401f758e6ca2460b0992f3d55dda8b
Merge "Whitebox server expects deleted > 0"