fix missing format param
fix missing format param

Signed-off-by: Ben Parees <bparees@redhat.com>

Closes: #1083
Approved by: rhatdan

TomSweeneyRedHat/buildah,nalind/buildah,TomSweeneyRedHat/buildah,nalind/buildah,ipbabble/buildah,rhatdan/buildah,nalind/buildah-1,rhatdan/buildah,nalind/buildah-1,projectatomic/buildah,projectatomic/buildah,projectatomic/buildah,TomSweeneyRedHat/buildah,nalind/buildah-1,rhatdan/buildah,ipbabble/buildah