package/sysstat: security bump to version 12.6.1

Fix CVE-2022-39377: sysstat is a set of system performance tools for the
Linux operating system. On 32 bit systems, in versions 9.1.16 and newer
but prior to 12.7.1, allocate_structures contains a size_t overflow in
sa_common.c. The allocate_structures function insufficiently checks
bounds before arithmetic multiplication, allowing for an overflow in the
size allocated for the buffer representing system activities. This issue
may lead to Remote Code Execution (RCE).

Despite what is written above in the CVE announcement, and as written in
the Changelog, the fix is also included in version 12.6.1 (12.7.1 is a
development version):
    https://github.com/sysstat/sysstat/commit/c1e631eddc50c04e4dcea169ba396bee2bd6b0ab

As a consequence, 12.6.1 is still reported as being affected. Until the
NVD is updated appropriately, we mark the CVE as ignored with a comment
that explains why.

Note: that commit is not reachable from any branch in the sysstat
repository, and Github warns about that, but the commit does belong to
the upstream repository and is reachable from the 12.6.1 tag (it looks
like sysstat only pushes tags-with-history for fix releases).

https://github.com/sysstat/sysstat/security/advisories/GHSA-q8r6-g56f-9w7x
https://github.com/sysstat/sysstat/blob/v12.6.1/CHANGES



Signed-off-by: Fabrice Fontaine <fontaine.fabrice@gmail.com>
[yann.morin.1998@free.fr:
  - ignore the CVE, explain why
  - explain why github warns about the fix commit
]
Signed-off-by: Yann E. MORIN <yann.morin.1998@free.fr>