FindGTK2: gthread-2.0 folder does not exist

Partially revert commit 508e8ca024e47baea342da85c7bbd014c7fd6c30
FindGTK2: Detect gmodule library
Merge topic 'FindGTK2-gmodule' into next

7ca5958 FindGTK2: Detect gmodule library
76c72b9 FindGTK2: gthread-2.0 folder does not exist