Partition mount fails if /media doesn't exist

[HughJass]

grub-customizer will faill to mount any partition if the /media directory doesn't exist (I guess it exist on Ubuntu, but doesn't on Manjaro). Since mounting requires root you might as well call mkdir. Also, the GUI error message is not helpful, only saying "mounting failed". Thankfuly there was a specific error message in the terminal when I launched grub-customizer from it.