Merge branch 'sg/httpd-test-unflake'

httpd tests saw occasional breakage due to the way its access log gets inspected by the tests, which has been updated to make them less flaky. * sg/httpd-test-unflake: t/lib-httpd: avoid occasional failures when checking access.log t/lib-httpd: add the strip_access_log() helper function t5541: clean up truncating access log