fix broken key pair check
fix broken key pair check

Signed-off-by: Yuechuan Chen <b9ffce55a1f8a1f79df40b13bc847b3da642deee@motorolasolutions.com>

johnsandiford/notary,vdemeester/notary,jfrazelle/notary,umayr/notary,umayr/notary,umayr/notary,endophage/notary,jfrazelle/notary,docker/notary,endophage/notary,docker/notary,HuKeping/notary,HuKeping/notary,vdemeester/notary,vdemeester/notary,HuKeping/notary,johnsandiford/notary,docker/notary,johnsandiford/notary,jfrazelle/notary,endophage/notary