[task scheduler] Fix pubsub client

Always ACK messages.

Bug: skia:
Change-Id: Idd829872ec36aec95db0f6b1fcdbd2e5fccfcf9b
Reviewed-on: https://skia-review.googlesource.com/c/179740
Reviewed-by: Ben Wagner <benjaminwagner@google.com>
Commit-Queue: Eric Boren <borenet@google.com>
diff --git a/task_scheduler/go/db/pubsub/modified.go b/task_scheduler/go/db/pubsub/modified.go
index 0d95504..9d18ede 100644
--- a/task_scheduler/go/db/pubsub/modified.go
+++ b/task_scheduler/go/db/pubsub/modified.go
@@ -134,7 +134,7 @@
 		}
 		if err := c.errors[id]; err != nil {
 			sklog.Warningf("modifiedClient is in error state; ignoring all messages.")
-			return err
+			return nil
 		}
 		// If the sender has changed, refuse the new messages and store
 		// an error. The error will be returned on the next call to
@@ -144,9 +144,9 @@
 		if c.senderId[id] == "" {
 			c.senderId[id] = senderId
 		} else if senderId != c.senderId[id] {
-			err := fmt.Errorf("Message has unknown sender %s (expected %s); not ack'ing.", senderId, c.senderId)
+			err := fmt.Errorf("Message has unknown sender %s (expected %s); not ack'ing.", senderId, c.senderId[id])
 			c.errors[id] = err
-			return err
+			return nil
 		}
 		prev, ok := c.modified[id][dataId]
 		if !ok || prev.ts.Before(dbModified) {