Double "\" in path name in specific situations

[Max33Verstappen]

If a path with a trailing \ but without quotes (which implies it doesn't have spaces in it) is passed to MPC-HC, eg: (a BD Folder)
\\XXX-NAS\test\
It becomes \\XXX-NAS\test\\BDMV\index.bdmv opened by MPC-HC (note the \\ after the "test").
Seem that the issue isn't present with quotes surrounding it.

[adipose]

This is specific to bluray folders. I could not reproduce with DVD. But fixed it.

#2814