CC-5802: Upgrade application.ini file

Used a transaction for upgrades. If upgrading the application.ini file fails, the database upgrades will get rolled back.
Merge branch 'cc-5709-airtime-analyzer' of github.com:sourcefabric/Airtime into cc-5709-airtime-analyzer
Merge branch 'cc-5709-airtime-analyzer' into cc-5709-airtime-analyzer-saas

Conflicts:
	airtime_mvc/application/controllers/UpgradeController.php