Effect maker temp folders cannot be removed

The effect maker on Mac creates shader files under /private/var/folders and this can create situation where Effect maker cannot be started anymore.

Steps to repro:

• Install Qt DS 3.8 and create effectMore
• Install another copy of Qt DS and try to open effect maker

Expected outcome:

• Effect maker opens on the UI

Actual outcome:

• Effect maker is seen on the taskbar but it does not open on the UI
• Analysing with dTruss reveals that it's trying to open shader templates under /private/var/folders where it does not have access rights 

100% repro