This random error is due to the different swap space at different
test hosts. In particular, there is a provider who provides VMs with
0 swap space, while other providers provide VMs with 8G swap space.
As a result, Magnum jobs failed at VMs with 0 swap space.
This commit reduces memory consumption of Magnum jobs by reducing the
bay node flavor from 2G to 1G. I consider this as a temporary fix.
A permanent fix should be from infra side to make the swap space
consistent across test nodes.
Partial-Bug: #1521237
Change-Id: Ia043fab1f7665f7299e4094634e02c42b43dcce1
958e63341a