compactor: fix error message of Revision compactor

Reorder the parameters so that Noticef can output the error properly.

compactor/compactor.go

@@ -105,7 +105,7 @@ func (t *Periodic) Run() {
 				last = clock.Now()
 				plog.Noticef("Finished auto-compaction at revision %d", rev)
 			} else {
-				plog.Noticef("Failed auto-compaction at revision %d (%v)", err, rev)
+				plog.Noticef("Failed auto-compaction at revision %d (%v)", rev, err)
 				plog.Noticef("Retry after %v", checkCompactionInterval)
 			}
 		}