Fix proxy memory leak. am: 25508806b8
am: fc12902fc7

Change-Id: I966ff8af9c5606144881d89163f30538079f2841
diff --git a/transport/HidlBinderSupport.cpp b/transport/HidlBinderSupport.cpp
index d293542..fe1ccbc 100644
--- a/transport/HidlBinderSupport.cpp
+++ b/transport/HidlBinderSupport.cpp
@@ -35,9 +35,10 @@
 
 void hidl_binder_death_recipient::binderDied(const wp<IBinder>& /*who*/) {
     sp<hidl_death_recipient> recipient = mRecipient.promote();
-    if (recipient != nullptr) {
+    if (recipient != nullptr && mBase != nullptr) {
         recipient->serviceDied(mCookie, mBase);
     }
+    mBase = nullptr;
 }
 
 wp<hidl_death_recipient> hidl_binder_death_recipient::getRecipient() {