QbsProjectManager: wrong import removes project name

Steps to reproduce:

• open/create simple Qbs project
• open one of the qbs files
• type 'import qbs.' and select one of the suggestions (I've used 'fileinfo')
• save without further modification

Current result:

• reparsing brings up 1 error, 1 warning and removes the project name (as well as other qbs files) from Projects list on the left
• run/debug button stay disabled until triggering a reparse without the error