Previously, if a secret became unavailable in barbican, the user saw
a generic error raised from the barbican client and was unable to delete
load balancer resources. This patch corrects both of those issues.
Change-Id: I97bd1b2a97a44d0a0566ae56167fa4f2e503ee2d
Story: 2006676
Task: 37012
Task: 37077
(cherry picked from commit 7fcef817ec)