Bug#1057107: bullseye-pu: package libssh2/1.9.0-2

[Nicolas Mora <babelouest@debian.org>]

Package: release.debian.org
Severity: normal
Tags: bullseye
User: release.debian.org@packages.debian.org
Usertags: pu
X-Debbugs-Cc: libssh2@packages.debian.org, team@security.debian.org
Control: affects -1 + src:libssh2

[ Reason ]
Fix CVE-2020-22218
https://security-tracker.debian.org/tracker/CVE-2020-22218

[ Impact ]
allows attackers to access out of bounds memory

[ Checklist ]
  [x] *all* changes are documented in the d/changelog
  [x] I reviewed all changes and I approve them
  [x] attach debdiff against the package in (old)stable
  [x] the issue is verified as fixed in unstable

[ Changes ]
This is a backport of the PR 476