pgsql: OpenSSL 3.0.0 compatibility in tests

OpenSSL 3.0.0 compatibility in tests

DES has been deprecated in OpenSSL 3.0.0 which makes loading keys
encrypted with DES fail with "fetch failed".  Solve by changing the
cipher used to aes256 which has been supported since 1.0.1 (and is
more realistic to use anyways).

Note that the minimum supported OpenSSL version is 1.0.1 as of
7b283d0e1d1d79bf1c962d790c94d2a53f3bb38a, so this does not introduce
any new version requirements.

Author: Daniel Gustafsson <daniel@yesql.se>
Discussion: https://www.postgresql.org/message-id/flat/FEF81714-D479-4512-839B-C769D2605F8A%40yesql.se

Branch
------
master

Details
-------
https://git.postgresql.org/pg/commitdiff/f0d2c65f17cab8cfaf4d39f7f8e2254824cd4092

Modified Files
--------------
src/test/ssl/Makefile                |  2 +-
src/test/ssl/ssl/server-password.key | 52 ++++++++++++++++++------------------
2 files changed, 27 insertions(+), 27 deletions(-)