If a tenant quota is not found, the delete operation should fail
with a 404 error. It currently returns 204 even if the delete
operation actually does not delete anything which is inconsistent
with other delete operations in the Neutron API.
APIImpact
Change-Id: I1cd91b5e06bd17f9aac97bba71228f2e5c48879b
Closes-Bug: 1307506
Co-Authored-By: Salvatore Orlando <salv.orlando@gmail.com>