Bug#986891: decbargo: can't find yanked crates.

[peter green]

Package: debcargo

Debcargo can't find yanked crates, even when the yanked version is explicitly requested
through the "REALVER" environment variable.

Some crate upstreams will yank all the existing versions after posting a security
or other important fix. Since Debian policies/practices during freezes (and for stable
releases) often requires backporting fixes rather than packaging new upstream versions,
this can be a problem.

[Blair Noctis]

Post by peter green
Package: debcargo
Debcargo can't find yanked crates, even when the yanked version is explicitly
requested through the "REALVER" environment variable.
Some crate upstreams will yank all the existing versions after posting a
security or other important fix. Since Debian policies/practices during
freezes (and for stable releases) often requires backporting fixes rather
than packaging new upstream versions, this can be a problem.

cargo can't find yanked crates either, even when the yanked version is
explicitly requested through `cargo add ***@1.2.3` - that's what yanking is for!

All hope is not lost though. Trying to fix it means it's already uploaded to
Debian, so there must be an orig.tar - just work with it the "old" way.