Modified version check on openssl so that it finds the executable

Modified version check on openssl so that it finds the executable
first and then performs a check of the version, only warning the
user if they chose, or we selected, an old version of OpenSSL.
This change also allows the code to work for non-openssl libraries
selected via the --with-ssl=dir option, which can override the
automated library check in any case.

git-svn-id: https://svn.apache.org/repos/asf/httpd/httpd/trunk@96345 13f79535-47bb-0310-9956-ffa450edef68