SMB shared disc data custom configuration not loading since PR#8975

I've been having this issue on the last few builds of rpcs3, it seems it goes all the way back to PR#8975, Build 0.0.12-10946.

Specifics:

• Windows 10 Pro x64, latest feature update
  
• Disc game data being hosted on SMB share on NAS - not directly mapped.  E.g., "\\servername\ROMs\Sony Playstation 3\3D Dot Game Heroes (BLUS30490)\"
  
• Emulator installed locally on HDD, \dev_hdd0\ and \dev_hdd1\ have not been relocated in any way (they exist as subfolders in the emulator's directory)
  

Example:

• Global configuration set to use Vulkan.
  
• Create custom configuration for game (in this case, BLUS30490 - 3D Dot Game Heroes). 
  
• Set renderer to OpenGL in custom configuration.
  
• Right click on game and choose "Boot with custom configuration"
  

Result:

• Emulator boots game in Vulkan mode and not OpenGL mode.
  
• rpcs3 log misidentifies game as "EBOOT.BIN"
  
• rpcs3 log does not show any attempt to use custom configuration file
  
• Game fails to launch
  

On PR#8982, Build 0.0.12-10945, however, it upholds the custom config, reflects the name properly, and boots the game in OpenGL mode. 

I've attached rpcs3 logs for both working and non-working builds.  HDD based games work fine as they are stored locally on the same HDD as the emulator. 

It appears that something in build 0.0.12-10946 with how it parses path names has caused it not to be able to properly read the game data or custom configurations if the game data is hosted on a network share that isn't directly mapped to a drive letter.