identity.key is no longer a file that jenkins tracks.

playbooks/roles/jenkins_admin/templates/edx/var/jenkins/jobs/backup-jenkins/config.xml.j2

@@ -27,7 +27,6 @@ mkdir -p $BUILD_ID/jobs
 # Copy global configuration files into the workspace
 cp $JENKINS_HOME/*.xml $BUILD_ID/
 # Copy keys and secrets into the workspace
-cp $JENKINS_HOME/identity.key $BUILD_ID/
 cp $JENKINS_HOME/secret.key $BUILD_ID/
 cp $JENKINS_HOME/secret.key.not-so-secret $BUILD_ID/
 cp -r $JENKINS_HOME/secrets $BUILD_ID/