Fix issue where snapshot could not be found if a sibling snapshot contai...

Fixes the following issue:

Given a tree like this:

+--parent_snapshot1
+--parent_snapshot2
+--+--child_snapshot2

find_node will return 'nil' when searching for 'parent_snapshot1' because the tree will iterate to parent_snapshot2, which has children, which will cause the recursive call on old line 110 to be called and return 'nil'.