'update' *RemovalPoliciesMode during 'node delete' can result in
undesired behaviour as we flush the blacklist history and use
the freshly constructed blacklist and decrease the node count.
Change-Id: Iebd0089b6ab35c84e4f20e83f1990c1c5568017f
Closes-Bug: #1848651
(cherry picked from commit 8f5c494150)