config: fix duplication of replication priority key (#17014)

internal/config/config.go

@@ -602,6 +602,17 @@ var renamedSubsys = map[string]string{
 	// Add future sub-system renames
 }
 
+const ( // deprecated keys
+	apiReplicationWorkers       = "replication_workers"
+	apiReplicationFailedWorkers = "replication_failed_workers"
+)
+
+// map of subsystem to deleted keys
+var deletedSubSysKeys = map[string][]string{
+	APISubSys: {apiReplicationWorkers, apiReplicationFailedWorkers},
+	// Add future sub-system deleted keys
+}
+
 // Merge - merges a new config with all the
 // missing values for default configs,
 // returns a config.
@@ -632,9 +643,16 @@ func (c Config) Merge() Config {
 				}
 				subSys = rnSubSys
 			}
+			// Delete deprecated keys for subsystem if any
+			if keys, ok := deletedSubSysKeys[subSys]; ok {
+				for _, key := range keys {
+					ckvs.Delete(key)
+				}
+			}
 			cp[subSys][tgt] = ckvs
 		}
 	}
+
 	return cp
 }