unix.sh - fix mkdir issue

[lyoneel]

fix issue when creating directory where input file of a video is in the same directory to output and has relative path.

Given: /usr/bin/upscaler --model upscayl-ultrasharp \ --scale 2 \ --format png \ --video \ --input my-video.mp4 \ --output my-video-upscaled

The program tries to create a directory ./my-video.mp4/something/something throws an error and stop the execution

This fix uses "my-video" instead of "my-video.mp4" as subject dir if subject_dir is equal to input.

[hollowaykeanho]

Thanks. I will accept and give it a run. Note that unless it breaks the core functionalities, I won't be patching further since my team is creating a new polygot scripts from scratch (init/start*) with CI maintainability.

[lyoneel]

I will not get offended if its reverted, no worries.

Thanks!