lib/oe/package_manager: import rpm signing key to rpmdb
Import the gpg key used in rpm signing into rpmdb. This makes it
possible again to create images when rpm signing is enabled.
Also, instruct dnf to enforce signature check if rpm signing is enabled.
Signed-off-by: Markus Lehtonen <markus.lehtonen@linux.intel.com> Signed-off-by: Alexander Kanavin <alexander.kanavin@linux.intel.com> Signed-off-by: Richard Purdie <richard.purdie@linuxfoundation.org>
