libnet-ssleay-perl: avoid host contamination

Check the configure log, libnet-ssleay-perl uses host's openssl:

*** Found OpenSSL-1.0.1 installed in /usr

Export OPENSSL_PREFIX to find the native openssl to use.

Replace library pathes '/lib', '/usr/lib' and header path with correct
staging pathes at same time.

Signed-off-by: Kai Kang <kai.kang@windriver.com>
Signed-off-by: Martin Jansa <Martin.Jansa@gmail.com>