openssl: fix pinned public key build error in FIPS mode

Here is a version that should work with all versions of openssl 0.9.7
through 1.1.0.

Links to the docs:
https://www.openssl.org/docs/man1.0.2/crypto/EVP_DigestInit.html
https://www.openssl.org/docs/man1.1.0/crypto/EVP_DigestInit.html

At the very bottom of the 1.1.0 documentation there is a history section
that states, " stack allocated EVP_MD_CTXs are no longer supported."

If EVP_MD_CTX_create and EVP_MD_CTX_destroy are not defined, then a
simple mapping can be used as described here:
https://wiki.openssl.org/index.php/Talk:OpenSSL_1.1.0_Changes

Closes #2258