examples/ct: add convenience local var
examples/ct: add convenience local var

RJPercival/trillian,gdbelvin/trillian,AlCutter/trillian,gtank/trillian,gdbelvin/trillian,codingllama/trillian,daviddrysdale/trillian,AlCutter/trillian,Martin2112/trillian,daviddrysdale/trillian,Martin2112/trillian,RJPercival/trillian,gtank/trillian,google/trillian,codingllama/trillian,daviddrysdale/trillian,gdbelvin/trillian,google/trillian,Martin2112/trillian