Don't pass a nil error to errors.Wrapf()
Don't pass a nil error to errors.Wrapf()

Don't pass a nil error value to errors.Wrapf() when we want to report an
error, since it's documented as returning nil for that case.

Signed-off-by: Nalin Dahyabhai <nalin@redhat.com>

Closes: #856
Approved by: rhatdan

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