Log Successful Snapshot Abort (elastic#62707)

We were missing a log statement for snapshots that could be aborted
directly due to the optimization in elastic#62173. Without logging added
we get no logging whatsoever and snapshots disappear without
anything logged at info level which makes debugging unnecessarily
complex.

Author: original-brownbear

server/src/main/java/org/elasticsearch/snapshots/SnapshotsService.java

@@ -1248,6 +1248,9 @@ public void onFailure(String source, Exception e) {
 
             @Override
             public void clusterStateProcessed(String source, ClusterState oldState, ClusterState newState) {
+                if (completedNoCleanup.isEmpty() == false) {
+                    logger.info("snapshots {} aborted", completedNoCleanup);
+                }
                 for (Snapshot snapshot : completedNoCleanup) {
                     failSnapshotCompletionListeners(snapshot,
                         new SnapshotException(snapshot, SnapshotsInProgress.ABORTED_FAILURE_TEXT));