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

t/t5561-http-backend.sh

@@ -129,13 +129,7 @@ GET  /smart/repo.git/info/refs?service=git-receive-pack HTTP/1.1 403 -
 POST /smart/repo.git/git-receive-pack HTTP/1.1 403 -
 EOF
 test_expect_success 'server request log matches test results' '
-	sed -e "
-		s/^.* \"//
-		s/\"//
-		s/ [1-9][0-9]*\$//
-		s/^GET /GET  /
-	" >act <"$HTTPD_ROOT_PATH"/access.log &&
-	test_cmp exp act
+	check_access_log exp
 '
 
 stop_httpd