Creator crashes on session switch

To reproduce:
1. Prepare two sessions (one with creator master, one with creator 2.8)
2. Run creator, open session with creator 2.8
3. Do some change (I added empty line to editorconfiguration.h). Ensure your change will take creator some time to compile (that's why I changed the header file)
4. Build All
5. During building switch to session with creator master - crash