openssl: add ppc64 patches.

See: packages#682 (closed)

This currently blocks the Spack bootstrap process on ppc64.

The patches in question are derived from:

• https://github.com/openssl/openssl/commit/34ab13b7d8e3e723adb60be8142e38b7c9cd382a
• https://github.com/openssl/openssl/commit/098404128383ded87ba390dd74ecd9e2ffa6f530

But they are modified slightly to be applied to openssl 1.x.