Configure the system-wide TCP connection timeout on OpenBSD

As there's no TCP connection timeout socket option that we can use, we
need to configure the TCP connection timeout system-wide in the CI, so
the netmgr unit tests doesn't cause assertion failure when there stuck
outgoing TCP connection waiting for 150 second timeout.

.gitlab-ci.yml

@@ -383,6 +383,7 @@ stages:
   <<: *default_triggering_rules
   stage: unit
   before_script:
+    - if [ -n "$TCP_CONNECTIONTIMEOUT" ]; then sudo sysctl 'net.inet.tcp.keepinittime=1'; fi
     - *setup_softhsm
   script:
     - make -j${TEST_PARALLEL_JOBS:-1} -k unit V=1
@@ -1216,6 +1217,8 @@ unit:clang:openbsd:amd64:
   <<: *unit_test_job
   variables:
     USER: gitlab-runner
+    # There's no socket option on OpenBSD, so we need to set this globally
+    TCP_CONNECTIONTIMEOUT: 1
   needs:
     - job: clang:openbsd:amd64
       artifacts: true