ci: stop special-casing for Ubuntu 16.04

With c85bcb5 (gitlab-ci: switch from Ubuntu 16.04 to 20.04,
2024-10-31) we have adapted the last CI job to stop using Ubuntu 16.04
in favor of Ubuntu 20.04. Remove the special-casing we still have in our
CI scripts.

Signed-off-by: Patrick Steinhardt <ps@pks.im>
Signed-off-by: Junio C Hamano <gitster@pobox.com>

Author: pks-t

ci/lib.sh

@@ -347,14 +347,7 @@ ubuntu-*)
 	fi
 	MAKEFLAGS="$MAKEFLAGS PYTHON_PATH=/usr/bin/$PYTHON_PACKAGE"
 
-	case "$distro" in
-	ubuntu-16.04)
-		# Apache is too old for HTTP/2.
-		;;
-	*)
-		export GIT_TEST_HTTPD=true
-		;;
-	esac
+	export GIT_TEST_HTTPD=true
 
 	# The Linux build installs the defined dependency versions below.
 	# The OS X build installs much more recent versions, whichever