oleaut32: Clear the input pvar structure in VARIANT_UserUnmarshal to free the…

dlls/oleaut32/tests/usrmarshal.c

@@ -1188,7 +1188,6 @@ static void test_marshal_VARIANT(void)
            V_VT(V_VARIANTREF(&v)), V_VT(V_VARIANTREF(&v3)));
         ok(V_R8(V_VARIANTREF(&v)) == V_R8(V_VARIANTREF(&v3)), "r8s differ\n");
         VARIANT_UserFree(&umcb.Flags, &v3);
-        todo_wine
         ok(heap_unknown->refs == 1, "%d refcounts of IUnknown leaked\n", heap_unknown->refs - 1);
         IUnknown_Release((IUnknown *)heap_unknown);
     }

dlls/oleaut32/usrmarshal.c

@@ -554,7 +554,7 @@ unsigned char * WINAPI VARIANT_UserUnmarshal(ULONG *pFlags, unsigned char *Buffe
     TRACE("(%x,%p,%p)\n", *pFlags, Buffer, pvar);
 
     ALIGN_POINTER(Buffer, 7);
-    VariantInit(pvar);
+    VariantClear(pvar);
 
     header = (variant_wire_t *)Buffer;