We have many places where we implement singleton behavior for the
placement client. This unifies them into a single place and
implementation. Not only does this DRY things up, but may cause us
to initialize it fewer times and also allows for emitting a common
set of error messages about expected failures for better
troubleshooting.
Change-Id: Iab8a791f64323f996e1d6e6d5a7e7a7c34eb4fb3
Related-Bug: #1846820
(cherry picked from commit c178d9360665c219cbcc71c9f37b9e6e3055a5e5)
77273f067d