removed assert from dnf_package_get_rpmdbid
removed assert from dnf_package_get_rpmdbid

according to documentation comment, this function can return 0

rpm-software-management/libhif,rpm-software-management/libhif,hughsie/libhif,rpm-software-management/libhif,rpm-software-management/libhif,Conan-Kudo/libhif,Conan-Kudo/libhif,Conan-Kudo/libhif,rpm-software-management/libdnf,rpm-software-management/libdnf,rpm-software-management/libdnf,hughsie/libhif,Conan-Kudo/libhif,hughsie/libhif,hughsie/libhif,rpm-software-management/libdnf