Bug#1001655: Avoid hardcoding depends on specific lzip implementations

[Daniel Baumann <daniel.baumann@progress-linux.org>]

Hi Felix,

> Looking at your documentation [1] does that mean Lintian can only
> offer the alternatives except lzd?

yes; to make that easier.. given that lzd is the only one that doesn't 
support '--test', I've dropped it from the alternatives handling and 
updated README.Debian accordingly:

https://git.progress-linux.org/users/daniel.baumann/debian/packages/lzip/commit/?id=aa00b3c1e8eb3ce2dbe4425a492240c2d54e5153

means.. you can now safely depend on "lzip | lzip-decompressor"
(or even better: "plzip | lzip-decompressor").

any of the lzip packages providing lzip-decompressor will support
'--test' and work for that lintian use-case. I'm keeping it that way as
a base-line, so any potential further lzip decompressor that woudn't 
support '--test' will not get the lzip-alternative handling.

> Or, is there another way to assess the actual nature or integrity of a
> file named like *.lz?

using '--test' is the proper way to do it.

Regards,
Daniel