As has been outlined in the DEPRECATE.md document, the axTLS code has
been disabled for 6 months and is hereby removed.
Use a better supported TLS library!
Assisted-by: Daniel Gustafsson
Closes#3194
SSLeay was the name of the library that was subsequently turned into
OpenSSL many moons ago (1999). curl does not work with the old SSLeay
library since years. This is now reflected by only using USE_OPENSSL in
code that depends on OpenSSL.