lib/oe/lsb: prefer /etc/os-release for distribution data
os-release(5) is an increasingly standard source of operating system
identification and more likely to be present on modern OS deployments, i.e.
many container variants of common distros include os-release and not the
lsb_release tool.
Therefore we should favour parsing /etc/os-release in distro_identifier(),
try lsb_release when that fails and finally fall back on various distro
specific sources of OS identification.
Signed-off-by: Joshua Lock <joshua.g.lock@intel.com> Signed-off-by: Ross Burton <ross.burton@intel.com>
