Installer crashes when running package manager twice without installing anything

I could reproduce this issue with the MaintenanceTool provided by Qt5.1.0.

Steps to reproduce:

• start the MaintenanceTool.app
• check 'Package Manager'
• Continue but don't select or deselect something on the next pages
• when 'installation' is done - hit the 'Restart' button
• check 'Package Manager' again
• Continue

Current result:

• Segmentation fault

Expected result:

• no crash

Note: See also attached crash logs.