Fix delete_vm test for postgresql
Fix delete_vm test for postgresql

[#120471359](https://www.pivotaltracker.com/story/show/120471359)

Signed-off-by: Konstantin Maksimov <a5df40d25e2dfebc7739577cd172a3af5b6b8b7c@ru.ibm.com>

barthy1/bosh,barthy1/bosh,barthy1/bosh,barthy1/bosh