Simplify the ! case
Simplify the ! case

From https://stackoverflow.com/a/42071865/4400820

I spent hours trying to get filter(map(buflisted), not empty or current)
to work, and something was impossibly hairy.

The second bdelete # deletes the 'blank file' created after %bdelete.

benknoble/Dotfiles,benknoble/Dotfiles,benknoble/Dotfiles,benknoble/Dotfiles,benknoble/Dotfiles