Today we log a "deleting snapshots [...] from repository [...]" message at INFO level [almost the first thing](https://github.com/elastic/elasticsearch/blob/dfaec0dbf0c8a0ba2912381334019725848f1f5a/server/src/main/java/org/elasticsearch/snapshots/SnapshotsService.java#L1886-L1888) when we start the deletion. However, the requested snapshots may not exist or they may be wildcards to be matched against actual snapshots. In these cases, the log message is either misleading or insuffiicent. Instead we should log the message after we have successfully added the delete to the cluster state similar to how the [logging works for snapshot creation](https://github.com/elastic/elasticsearch/blob/f77c16b78bab5e9f3ee24974aeba408e254e8c94/server/src/main/java/org/elasticsearch/snapshots/SnapshotsService.java#L3804).
server/src/main/java/org/elasticsearch/snapshots/SnapshotsService.java
assert reposWithRunningDelete.contains(entry.repository()) == false
                        : "Found shard snapshot actively executing in ["
                            + entry
                            + "] when it should be blocked by a running delete ["
                            + Strings.toString(snapshotDeletionsInProgress)
                            + "]";
                }
            }
        }
        return true;
    }
    /**
     * Updates the state of in-progress snapshots in reaction to a change in the configuration of the cluster nodes (master fail-over or
     * disconnect of a data node that was executing a snapshot) or a routing change that started shards whose snapshot state is
     * {@link SnapshotsInProgress.ShardState#WAITING}.
     *
     * @param changedNodes true iff either a master fail-over occurred or a data node that was doing snapshot work got removed from the
     *                     cluster
     * @param startShards  true iff any waiting shards were started due to a routing change
     */
    private void processExternalChanges(boolean changedNodes, boolean startShards) {
        if (changedNodes == false && startShards == false) {
            
            return;
        }
        final String source = "update snapshot after shards started ["
            + startShards
            + "] or node configuration changed ["
            + changedNodes
            + "]";