USB drive dismounts if last-accessed directory is missing

[rhester72]

Describe the bug
A mounted USB drive dismounts if the last-accessed directory is missing. The USB drive must be physically removed and re-attached in order to remount.

To Reproduce
Steps to reproduce the behavior:

1. Create a subdirectory (e.g. /media/usb/roms/commodore_ami/NTSC)
2. Place a disk image in the subdirectory and start the game
3. While the game is running, connect via SSH or FTP and delete both the game and subfolder
4. Open the Game List and the USB drive will be dismounted because ReplayOS can't find the current folder

NOTE: This may well affect any core and likely affects SSD, HDD and NFS as well

Expected behavior
If the last-accessed directory is missing, return to the top folder versus dismounting the USB drive entirely

NOTE: I have not tested behavior on native SD card, wanted to get this reported before I forgot

Setup:

• Device: Raspberry Pi 500
• OS version: v1.7.0
• Storage: USB
• Power adapter: Raspberry Pi official