Update all Dockerfiles to match/follow @witoff's changes after https://github.com/google/trillian/pull/667 is merged. Also, remove libtool dependency as soon as https://github.com/google/trillian/pull/734 is merged (related to https://github.com/google/keytransparency/issues/687).
Update all Dockerfiles to match/follow @witoff's changes after google/trillian#667 is merged.
Also, remove libtool dependency as soon as google/trillian#734 is merged (related to #687).