Bug#1100415: apt: Consider a more descriptive error message for `apt install ../non-existing.deb`

[Niels Thykier <niels@thykier.net>]

Package: apt
Version: 2.9.31
Severity: minor
X-Debbugs-Cc: niels@thykier.net

Hi,

Please consider to add "No such file or directory" as output for when 
passing a non-existing .deb to `apt install`. It would make it a not 
clearer to the user what is going wrong.

$ apt install ../non-existing.deb
Error: Unsupported file ../non-existing.deb given on commandline
$ ls ../non-existing.deb
ls: cannot access '../non-existing.deb': No such file or directory

Best regards,
Niels