remove fail_on_leak flag
diff --git a/test/end2end_test.go b/test/end2end_test.go
index 9461cd6..ff04c27 100644
--- a/test/end2end_test.go
+++ b/test/end2end_test.go
@@ -1354,8 +1354,6 @@
 	return
 }
 
-var failOnLeaks = flag.Bool("fail_on_leaks", true, "Fail tests if goroutines leak.")
-
 // leakCheck snapshots the currently-running goroutines and returns a
 // function to be run at the end of tests to see whether any
 // goroutines leaked.
@@ -1364,10 +1362,6 @@
 	for _, g := range interestingGoroutines() {
 		orig[g] = true
 	}
-	leakf := t.Logf
-	if *failOnLeaks {
-		leakf = t.Errorf
-	}
 	return func() {
 		// Loop, waiting for goroutines to shut down.
 		// Wait up to 5 seconds, but finish as quickly as possible.
@@ -1387,7 +1381,7 @@
 				continue
 			}
 			for _, g := range leaked {
-				leakf("Leaked goroutine: %v", g)
+				t.Errorf("Leaked goroutine: %v", g)
 			}
 			return
 		}