veyron/runtimes/google/ipc: Fix flaky test

This should fix failures like:
--- FAIL: TestProxy-16 (3.97 seconds)
	server_test.go:170: Got (, ipc: response header decoding failed: EOF) want ("", "RESOLVE: <err>") as proxy is down

(https://www.envyor.com/jenkins/job/veyron-go-race/1874/console)

Change-Id: I61025994c29550b2dc0039b2c0f9566d3fde58e2
diff --git a/runtimes/google/ipc/server_test.go b/runtimes/google/ipc/server_test.go
index 6453874..ebe2402 100644
--- a/runtimes/google/ipc/server_test.go
+++ b/runtimes/google/ipc/server_test.go
@@ -166,14 +166,14 @@
 	if err := proxy.Stop(); err != nil {
 		t.Fatal(err)
 	}
-	if result, err := makeCall(); err == nil || !strings.HasPrefix(err.Error(), "RESOLVE") {
-		t.Fatalf(`Got (%v, %v) want ("", "RESOLVE: <err>") as proxy is down`, result, err)
-	}
 	for {
 		if _, err := ns.Resolve(testContext(), name); err != nil {
 			break
 		}
 	}
+	if result, err := makeCall(); err == nil || !strings.HasPrefix(err.Error(), "RESOLVE") {
+		t.Fatalf(`Got (%v, %v) want ("", "RESOLVE: <err>") as proxy is down`, result, err)
+	}
 	verifyMountMissing(t, ns, name)
 
 	// Proxy restarts, calls should eventually start succeeding.