Fix accessing wrong item data of Compare refs list

Closed username-removed-94717 requested to merge YueLinHo/tortoisegit:fix into master

Regression of commit d6d37876f328d66791f94ba36a92a9a0c55bf553

It happened after sorting the Compare refs list


and hiding the unchanged item.


Because the index value of list control does not equal the index value of the m_RefList anymore.

Edited by username-removed-94717