cmd/gopherbot: improve clarity of log message

For golang/go#53077.

Change-Id: I877f1132c0e9e63947742d3b870d1742858091f7
Reviewed-on: https://go-review.googlesource.com/c/build/+/409654
Auto-Submit: Dmitri Shuralyov <[email protected]>
Reviewed-by: Dmitri Shuralyov <[email protected]>
Reviewed-by: Hyang-Ah Hana Kim <[email protected]>
Run-TryBot: Dmitri Shuralyov <[email protected]>
TryBot-Result: Gopher Robot <[email protected]>

Author: dmitshur

cmd/gopherbot/gopherbot.go

@@ -2081,9 +2081,9 @@ func (b *gopherbot) assignReviewersToCLs(ctx context.Context) error {
 			if ok {
 				return nil
 			}
+			log.Printf("humanReviewersOnChange reported insufficient reviewers or cc on CL %d, attempting to add some", cl.Number)
 
 			changeURL := fmt.Sprintf("https://go-review.googlesource.com/c/%s/+/%d", gp.Project(), cl.Number)
-			log.Printf("No reviewers or cc: %s", changeURL)
 			files, err := b.gerrit.ListFiles(ctx, gc.ID(), cl.Commit.Hash.String())
 			if err != nil {
 				log.Printf("Could not get change %+v: %v", gc, err)