osd/OSD.cc: parse lsb release data via lsb_release

Use lsb_release tool to be portable since parsing /etc/lsb-release
is not the same between different distributions. The old code failed
e.g. for SUSE products to parse LSB information.

Fixes: #8654

Signed-off-by: Danny Al-Gaaf <danny.al-gaaf@bisect.de>
Merge pull request #2017 from ceph/wip-8654

Fix #8654 - OSD.cc: parse LSB data via lsb_release

Reviewed-by: Sage Weil <sage@inktank.com>
Reviewed-by: Loic Dachary <loic@dachary.org>