Fix boost-python rules for Fedora

[cottsay]

No supported versions of Fedora carry a Python 2 subpackage for Boost. In Fedora 33, the boost-python3-devel subpackage was folded into boost-devel.

Fedora 30 and 31 are EOL - the currently supported Fedora versions are 32 and 33.

[hidmic]

I'm not entirely convinced we should remove keys for EOL Fedora versions. Kinetic is still alive and it used to target Fedora 26 according to REP-3. Can we be sure there's no one anywhere running a non-EOL distro on an EOL platform like these?

[cottsay]

I have mixed feelings about this. Fedora 26 reached EOL over 2 1/2 years ago, and unlike Ubuntu LTS, Fedora has no security maintenance options. Once a distro is EOL, there will be no updated packages, and users are expected to roll to a supported release.

We certainly can't be sure there's nobody trying to use an EOL platform like this (despite it being a really bad idea). Unfortunately, I don't think we have a concrete policy on the topic either (#18296).

FWIW, we've been dropping EOL distros from the distribution.yaml files pretty aggressively in the past (#18151, #18235).

[hidmic]

FWIW, we've been dropping EOL distros from the distribution.yaml files pretty aggressively in the past (#18151, #18235).

We should have a policy for these things 🙈

@clalancette @tfoote thoughts ?

[hidmic]

Alright, I won't block you here. We can revisit our policy later on.

[clalancette]

My general feeling is that we should indeed remove keys for really outdated distributions. Otherwise, we'll just have an ever-growing database.

On the other hand, I know when I've proposed doing this in the past, there have been complaints. In particular, people continue to use the rosdep database on way-past-EOL distributions, since that is what their robots use.

In this particular case, Fedora is a really fast-moving distribution. So I'm fine with dropping old keys from pretty old versions of it.