ole32: Discard existing data when creating a new storage on an ILockBytes.

dlls/ole32/storage32.c

@@ -2740,6 +2740,10 @@ static HRESULT StorageImpl_Construct(
     ULARGE_INTEGER size;
     BYTE bigBlockBuffer[MAX_BIG_BLOCK_SIZE];
 
+    /* Discard any existing data. */
+    size.QuadPart = 0;
+    ILockBytes_SetSize(This->lockBytes, size);
+
     /*
      * Initialize all header variables:
      * - The big block depot consists of one block and it is at block 0

dlls/ole32/tests/storage32.c

@@ -2971,7 +2971,7 @@ static void test_hglobal_storage_creation(void)
 
     r = StgOpenStorageOnILockBytes(ilb, NULL, STGM_READ|STGM_SHARE_EXCLUSIVE,
         NULL, 0, &stg);
-    todo_wine ok(r == S_OK, "StgOpenStorageOnILockBytes failed, hr=%x\n", r);
+    ok(r == S_OK, "StgOpenStorageOnILockBytes failed, hr=%x\n", r);
 
     if (SUCCEEDED(r))
     {