BugFix Update Checkbox in ScriptRepository

For some versions of Qt (it has been seen in Qt4.8), the Update column of ScriptRepository was not
displaying correctly. By, defining the correct state values, this commit
solves this issue.

re #7889
Better Visualization of update check in script repository

Solve the ugly view of the check box

re #7889
Merge remote-tracking branch 'origin/feature/7889_repo_check_box'