Add sample FFDH parameters file and use that in t_server_null tests

Change-Id: I13ad2b7da6b008bc692b1f08f502fc3fc57e7206
Signed-off-by: Samuli Seppänen <sasepp@pm.me>
Acked-by: Arne Schwabe <arne-openvpn@rfc2549.org>
Message-Id: <20250821121442.30679-1-gert@greenie.muc.de>
URL: https://www.mail-archive.com/openvpn-devel@lists.sourceforge.net/msg32643.html
Signed-off-by: Gert Doering <gert@greenie.muc.de>

Author: Samuli Seppänen

sample/sample-keys/ffdhe2048.pem

@@ -0,0 +1,8 @@
+-----BEGIN DH PARAMETERS-----
+MIIBCAKCAQEA//////////+t+FRYortKmq/cViAnPTzx2LnFg84tNpWp4TZBFGQz
++8yTnc4kmz75fS/jY2MMddj2gbICrsRhetPfHtXV/WVhJDP1H18GbtCFY2VVPe0a
+87VXE15/V8k1mE8McODmi3fipona8+/och3xWKE2rec1MKzKT0g6eXq8CrGCsyT7
+YdEIqUuyyOP7uWrat2DX9GgdT0Kj3jlN9K5W7edjcrsZCwenyO4KbXCeAvzhzffi
+7MA0BM0oNC9hkXL+nOmFg/+OTxIy7vKBg8P+OxtMb61zO7X8vC7CIAXFjvGDfRaD
+ssbzSibBsu/6iGtCOGEoXJf//////////wIBAg==
+-----END DH PARAMETERS-----

tests/t_server_null_default.rc

@@ -13,7 +13,7 @@ srcdir="${srcdir:-.}"
 top_builddir="${top_builddir:-..}"
 sample_keys="${srcdir}/../sample/sample-keys"
 
-DH="${sample_keys}/dh2048.pem"
+DH="${sample_keys}/ffdhe2048.pem"
 CA="${sample_keys}/ca.crt"
 CLIENT_CERT="${sample_keys}/client.crt"
 CLIENT_KEY="${sample_keys}/client.key"