Fix BINDER_LIB_TEST_NOP_CALL_BACK.

To write in the request Parcel instead of the reply Parcel.

Also fixed reading the callback return value to use
readInt32(&...), so we correctly set the status if
there was no data in the Parcel.

Test: binderLibTest passes
Change-Id: I1c5b075b6f1f6d19c40e7bf9589a94809ce414ff
diff --git a/libs/binder/tests/binderLibTest.cpp b/libs/binder/tests/binderLibTest.cpp
index 218b37e..1425940 100644
--- a/libs/binder/tests/binderLibTest.cpp
+++ b/libs/binder/tests/binderLibTest.cpp
@@ -331,10 +331,14 @@
             (void)reply;
             (void)flags;
             switch(code) {
-            case BINDER_LIB_TEST_CALL_BACK:
-                m_result = data.readInt32();
+            case BINDER_LIB_TEST_CALL_BACK: {
+                status_t status = data.readInt32(&m_result);
+                if (status != NO_ERROR) {
+                    m_result = status;
+                }
                 triggerEvent();
                 return NO_ERROR;
+            }
             case BINDER_LIB_TEST_CALL_BACK_VERIFY_BUF: {
                 sp<IBinder> server;
                 int ret;
@@ -1044,7 +1048,7 @@
                 if (binder == NULL) {
                     return BAD_VALUE;
                 }
-                reply2.writeInt32(NO_ERROR);
+                data2.writeInt32(NO_ERROR);
                 binder->transact(BINDER_LIB_TEST_CALL_BACK, data2, &reply2);
                 return NO_ERROR;
             }