package_manager.py: set dnf's releasever setting from DISTRO_CODENAME
So that:
1) dnf does not complain anymore about releasever not being set and then fail
for the same reason;
2) it's possible to refer to $releasever in dnf package feed configuration
(repo paths in particular) without hardconding the release name (pyro, morty, etc.)
(From OE-Core rev:
789e3fc225adbb61f10aaa3bbc3677856f5f0238)
Signed-off-by: Alexander Kanavin <alexander.kanavin@linux.intel.com>
Signed-off-by: Ross Burton <ross.burton@intel.com>
Signed-off-by: Richard Purdie <richard.purdie@linuxfoundation.org>
Signed-off-by: Armin Kuster <akuster808@gmail.com>
