meta/lib/oe/lsb.py: extract only the needed info from lsb-release
Instead of running lsb_release -a, a lsb_release -ir will be run.
This will prevent issue with distros that don't have all the needed
info in /etc/lsb-release file, in which case lsb_release won't generate
an error code.
Partial fix for [YOCTO #4071]
Signed-off-by: Cristian Iorga <cristian.iorga@intel.com> Signed-off-by: Richard Purdie <richard.purdie@linuxfoundation.org>
