Close ServerTransport instead of the raw connection

server.go

@@ -279,7 +279,7 @@ func (s *Server) serveNewHTTP2Transport(c net.Conn, authInfo credentials.AuthInf
 		return
 	}
 	if !s.addConn(st) {
-		c.Close()
+		st.Close()
 		return
 	}
 	s.serveStreams(st)

test/end2end_test.go

@@ -1354,7 +1354,7 @@ func interestingGoroutines() (gs []string) {
 	return
 }
 
-var failOnLeaks = flag.Bool("fail_on_leaks", false, "Fail tests if goroutines leak.")
+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