[update] [shDS] don't directly access vector data

This is because vector data is now possibly inlined and `data` could be
NULL.

While I could possibly make the vector continue setting `data` correctly
even in inline case, that would have been slightly less efficient.
Besides, this way seems a bit cleaner.

Signed-off-by: Shahbaz Youssefi <ShabbyX@gmail.com>