oeqa.utils.metadata: re-organise host distro information
Put all host distro data under one <host_distro> element. In addition
take the data directly from /etc/os-release instead of the "lsb API".
The /etc/os-release file is virtually ubiquitous, now, and using its
field names and values provides a more standardized and extensible
format.
[YOCTO #10590]
Signed-off-by: Markus Lehtonen <markus.lehtonen@linux.intel.com> Signed-off-by: Ross Burton <ross.burton@intel.com>
