Make a queue move lossless and run its passes on the acting controller alone (hq issue 558)

Review of #276: a move deleted before it published, so a failed publish
lost an ask; a verb's own process ran a pass beside the serving one, so
one could resume the queue while the other moved asks and a build ran
twice. The copy is now published first and second copies removed by id,
asks only signal the acting controller's loop, moves stop with 5 s of
the pause left, a cancel finds a moved ask by id, and an unreadable ask
keeps its age.

cmd/mesh-controller/queue_answer_test.go

@@ -142,3 +142,16 @@ func TestTheQueueNeverShowsARepositorysPassword(t *testing.T) {
 		}
 	}
 }
+
+// A cancel says it deleted the ask only when it did: moved into order and gone since, it says so (novox/hq
+// issue 558).
+func TestACancelSaysDeletedOnlyWhenItDeleted(t *testing.T) {
+	ask := link.QueuedAsk{ID: "build-1", Repository: "novox/x", State: link.AskWaiting, Seq: 4}
+	if said := cancelSaid(ask, link.TheBuildMachine, 9); !strings.Contains(said, "deleted from the") {
+		t.Errorf("removed, it says: %s", said)
+	}
+	if said := cancelSaid(ask, link.TheBuildMachine, 0); strings.Contains(said, "deleted from") ||
+		!strings.Contains(said, "no longer in the") {
+		t.Errorf("gone already, it says: %s", said)
+	}
+}