tests: keep headless environments minimal

tests/ibus_live_test.c

@@ -283,7 +283,6 @@ startdaemon(Daemon *d, char *program, char *mapdir)
 		setenv("XDG_CONFIG_HOME", d->config, 1);
 		setenv("HOME", d->home, 1);
 		unsetenv("DISPLAY");
-		unsetenv("WAYLAND_DISPLAY");
 		unsetenv("DBUS_SESSION_BUS_ADDRESS");
 		unsetenv("IBUS_ADDRESS");
 		execl(program, program, mapdir, missing, (char*)0);