Set brain_z1/z2 to update serially
Set brain_z1/z2 to update serially

[#88755820]

Signed-off-by: Eric Malm <f38766f3ef0e8328064f8aa2a19c8805448432f2@pivotal.io>

cloudfoundry-incubator/diego-release,cloudfoundry-incubator/diego-release,cloudfoundry-incubator/diego-release,cloudfoundry-incubator/diego-release