Fix auto allocate network cleanup

AutoAllocateNetworkTest.resource_cleanup was trying to delete all
networks instead of only networks in its tenant. This leads to
failures if there happens to be another network (created by
something else) in a different tenant, since the context used is
non-admin and therefore lacks policy permission to delete things
in other tenants. The cleanup is herein changed to only cleanup
networks in the relevant tenant.

Change-Id: Ibc00ca976472cac46bf611f626d315d7e644f650
Closes-Bug: #1698382
1 file changed