ncat: Update to 7.91 and fix #12647 ncat segfault if virtmanager try to connect libvirt

ncat: Update to 7.91 and fix #12647 ncat segfault if virtmanager try to connect libvirt

- Update from 7.80 to 7.91
- Update of rootfile
- Changelog is too long to include here
   Full details can be found in the CHANGELOG file in the source tarball
- Added patch to fix segfault - https://github.com/nmap/nmap/issues/2154
- Ran with unpatched 7.91 version
   $ touch /tmp/foo
   $ nc -U /tmp/foo
   Segmentation fault - flagged problem in #12647
- Ran with patched 7.91 version
   $ touch /tmp/foo
   $ nc -U /tmp/foo
   Ncat: Connection refused. - Expected behaviour

Tested-by: Adolf Belka <adolf.belka@ipfire.org>
Signed-off-by: Adolf Belka <adolf.belka@ipfire.org>
Reviewed-by: Michael Tremer <michael.tremer@ipfire.org>
Signed-off-by: Arne Fitzenreiter <arne_f@ipfire.org>