istio.io/istio/security/cmd/flexvolume/driver coverage dropped from 65 to 40 %

-istio.io/istio/security/cmd/flexvolume/driver:65 [67.6]
+istio.io/istio/security/cmd/flexvolume/driver:40 [42.7]

https://circleci.com/gh/istio/istio/41713#artifacts/containers/0