Some versions of openssl are not installed in `lib/`

In superbuild, some versions of libssl end up installed in lib64/ instead of lib/. Because of that, libcurl compilation fails.

When configuring, libdir options shall be forced to ${prefix}/lib instead of the default ${prefix}/lib64.

On HAL, I see OpenSSL_1_0_1p.tar.gz being installed by superbuild in lib64

HAL (CentOS 6, 64bits). OpenSSL_1_0_1p.tar.gz