Some rpm files were missing.
Most likely, you want to create these signed copies.

Missing files:
/mnt/koji/packages/ocaml-xenops/2.0.0/14.el7.centos/data/signed/3fd3ac9e/x86_64/ocaml-xenops-2.0.0-14.el7.centos.x86_64.rpm
/mnt/koji/packages/ocaml-xenops/2.0.0/14.el7.centos/data/signed/3fd3ac9e/x86_64/ocaml-xenops-devel-2.0.0-14.el7.centos.x86_64.rpm