Commit 7c5571690acef4a640f30e754bde5e133a66c33e

Edward Thomson 2018-10-21T10:34:38

ci: use trusty-amd64 for openssl and mbedtls We don't need two separate docker images for OpenSSL and mbedTLS. They've been combined into a single image `trusty-amd64` that supports both.