libarchive: Add support for building with OpenSSL 1.1

OpenSSL 1.1 made some CTX structures opaque.  Port our code to use the
structures only through pointers via OpenSSL 1.1 APIs.  Use our adaption
layer to make this work with OpenSSL 1.0 and below.

Patch-by: Tomas Mraz <tmraz@redhat.com>
Patch-from: https://bugzilla.redhat.com/1383744