perf: load test-lib-functions from the correct directory

Loading it in the subshells still referred to $TEST_DIRECTORY/..,
which was only correct in preliminary versions of perf-lib.sh

Signed-off-by: Thomas Rast <trast@student.ethz.ch>
Signed-off-by: Junio C Hamano <gitster@pobox.com>

t/perf/p0000-perf-lib-sanity.sh

@@ -38,4 +38,9 @@ test_expect_success 'test_export works with weird vars' '
 	test "$bar" = "weird # variable"
 '
 
+test_perf 'test-lib-functions correctly loaded in subshells' '
+	: >a &&
+	test_path_is_file a
+'
+
 test_done

t/perf/perf-lib.sh

@@ -119,7 +119,7 @@ test_run_perf_ () {
 	test_export_="test_cleanup"
 	export test_cleanup test_export_
 	/usr/bin/time -f "%E %U %S" -o test_time.$i "$SHELL" -c '
-. '"$TEST_DIRECTORY"/../test-lib-functions.sh'
+. '"$TEST_DIRECTORY"/test-lib-functions.sh'
 test_export () {
 	[ $# != 0 ] || return 0
 	test_export_="$test_export_\\|$1"