client: convert to use ct.LogEntryFromLeaf()
client: convert to use ct.LogEntryFromLeaf()

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