Remove "sudo: true" from Travis config
Remove "sudo: true" from Travis config

Travis says "deprecated key sudo (The key `sudo` has no effect anymore.)"

google/certificate-transparency-go,RJPercival/certificate-transparency-go,RJPercival/certificate-transparency-go,daviddrysdale/certificate-transparency-go,daviddrysdale/certificate-transparency-go,google/certificate-transparency-go,google/certificate-transparency-go,RJPercival/certificate-transparency-go,daviddrysdale/certificate-transparency-go