ID->IP mapping is added to the raft address map when the mapping first
appears in the gossiper, but it is added as expiring entry. It becomes
non expiring when a node is added to raft configuration. But when a node
joins those two events may be distant in time (since the node's request
may sit in the topology coordinator queue for a while) and mappings may
expire already from the map. This patch makes sure to transfer the
mapping from the gossiper for a node that is added to the raft
configuration instead of assuming that the mapping is already there.
(cherry picked from commit bddaf498df)