Bugfixes: better handling of date format in driver_cleanup, better handling "access denied" in msi_cleanup

Bugfixes:

• better handling of date format in driver_cleanup - it will now treat all "dates" that don't resemble a date (that is, are not a group of three numbers interspaced with "/" symbol) as simple strings; that should handle dates like "Unknown"
• better handling "access denied" in msi_cleanup: now it should provide a message "access denied" in English regardless of installed locale (so it should be readable on all systems)