Use MockEnv in test_pin_operator_digests
Use MockEnv in test_pin_operator_digests

* CLOUDBLD-73

Signed-off-by: Adam Cmiel <1217f9865bd733d1bcad0d0d64be310272c5592c@redhat.com>

projectatomic/atomic-reactor,fr34k8/atomic-reactor,fr34k8/atomic-reactor,DBuildService/atomic-reactor,projectatomic/atomic-reactor,DBuildService/atomic-reactor