pgsql: Remove incorrect OpenSSL feature guards

Remove incorrect OpenSSL feature guards

Commit 316472146 introduced support for ECDH key exchange with an ifdef
guard to ensure support in the underlying OpenSSL installation. Commit
10bf4fc2c3 in OpenSSL removed this guard in 2015 which effectively made
our check a no-op. There has been no complaints that this doesn't work
and OpenSSL installations without ECDH support are likely very rare, so
remove the checks rather than re-implementing support. Not backpatched
since this fix doesn't alter functionality.

Also fix a typo introduced in the original commit which had survived
till this day.

Author: Daniel Gustafsson <daniel(at)yesql(dot)se>
Reviewed-by: Tom Lane <tgl(at)sss(dot)pgh(dot)pa(dot)us>
Reviewed-by: Jacob Champion <jacob(dot)champion(at)enterprisedb(dot)com>
Discussion: https://postgr.es/m/1787BA9F-A11C-4A7A-9252-94C470D5CBE3@yesql.se

Branch
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master

Details
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https://git.postgresql.org/pg/commitdiff/c71b94f03304954e4352f96595254622b64f851c

Modified Files
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src/backend/libpq/be-secure-openssl.c | 4 ----
src/backend/libpq/be-secure.c | 2 +-
2 files changed, 1 insertion(+), 5 deletions(-)