Crash on code model update

Here it is reproducible by

• open a session holding a qbs build of QC
• before the project could be read completely start searching for a file of the project inside the locator (only typing, no Enter)

QC crashed while preparing codemodel.. but tbh it also might be some interference with qmljs (semantic info updater) - qml parsing almost finished (and started a 2nd one) and one of the qbs files where open inside QC after opening the session.