FindOpenSSL: Honor OPENSSL_ROOT_DIR everywhere (#14735)

In commit v2.8.5~176^2~2 (FindOpenSSL: We should only use hints to find
OpenSSL, 2011-03-28) values for HINTS and PATHS of find_* calls were
computed everywhere but only used on Windows.  Use them everywhere.
Merge topic 'FindOpenSSL-root-dir' into next

12d6eb63 FindOpenSSL: Honor OPENSSL_ROOT_DIR everywhere (#14735)