Remove libopenssl dep from NGINX_HTTP_CACHE and NGINX_HTTP_AUTH_BASIC config flag
The documentation doesn't mention that openssl is required for this 2 modules. This also permit to use nginx no-ssl variant without libopenssl as this 2 module are selected by default. Also make OPENSSL_ENGINE flag a dep to recompile nginx on change of openssl compilation flag.
Signed-off-by: Ansuel Smith <ansuelsmth@gmail.com>