Binder: Fix some valgrind errors.

When using 64 bit binder pointers, only initializing the 32 bit
handle, in a stack allocated struct, will pass uninitialized stack
data to the kernel and other processes.

Change-Id: I3432d9d36bb251d8ddb0a863661aeb80aabb3d92
diff --git a/libs/binder/IPCThreadState.cpp b/libs/binder/IPCThreadState.cpp
index 65329f5..35dba12 100644
--- a/libs/binder/IPCThreadState.cpp
+++ b/libs/binder/IPCThreadState.cpp
@@ -904,6 +904,7 @@
 {
     binder_transaction_data tr;
 
+    tr.target.ptr = 0; /* Don't pass uninitialized stack data to a remote process */
     tr.target.handle = handle;
     tr.code = code;
     tr.flags = binderFlags;