openssl: fix EVP_PKEY_CTX memory leak

openssl: fix EVP_PKEY_CTX memory leak

A context allocated with EVP_PKEY_CTX_new_id() must be ultimately free'd
by Eng VP_PKEY_CTX_free(). Failing to do so will result in a memory leak.

This bug was discovered using GCC with "-fsanitize=address".

Signed-off-by: Antonio Quartulli <antonio@openvpn.net>
Acked-by: Gert Doering <gert@greenie.muc.de>
Message-Id: <20210405080007.1665-1-a@unstable.cc>
URL: https://www.mail-archive.com/search?l=mid&q=20210405080007.1665-1-a@unstable.cc
Signed-off-by: Gert Doering <gert@greenie.muc.de>