For some reason, many users experince corrupted storage with the
ConfigMaps storage backend. Specifically, several Releases are marked as
DEPLOYED. This patch improved handling of such situations, by taking the latest
DEPLOYED Release. Eventually, the storage will clean itself out, after
the corrupted Releases are deleted due to --history-max.

Closes #6031

Signed-off-by: Cristian Klein <cristian.klein@elastisys.com>
(cherry picked from commit 840e0e27)