No warning is issued when directory is modified and no longer exists when attempting to backup files on shutdown

[monasar]

Problem description:

When the backup directory is modified e.g moving it to another location, renaming, or even deleting it, the BORG Calendar will not store the backup files provided that the user selected the backup option on shutdown. The user will be misled to believe that the BORG Calendar is actually creating backup files since no warning is given that the directory is missing.

Environment and Setup:

Hardware: Clevo Laptop, Desktop
OS: ArchLinux Kernal v.3.18.3, Windows 7
BORGCalendar Version: 1.8.1

How to reproduce:

1. Go to Options -> Edit preferences -> Miscellaneous tab
2. In the Backup Folder, browse and create a new folder as a directory.
   • create a folder called 'test', and save.
3. For the On Shutdown option: Select Backup to file
4. Delete or rename the directory you just created.
   • delete or rename 'test'
5. Close BORG Calendar. The backup files will not be stored and no notification of the directory not existing will be issued
6. Same behavior applies when selecting 'On Shutdown: Prompt for backup action'

Suggestion for Fix:

• If the directory selected in Backup Folder option was modified/no longer exists, create the directory and store the backup files there.
• Another solution, If the directory selected in Backup Folder option was modified/no longer exists, notify the user that the directory does not exist and hence no backup of the files are being stored.