BUG/MINOR: startup: dump libs only in worker if started with -W -dL

If haproxy was started with -W -dL, after master-worker refactoring we dump
libs to stdout twice in master and in worker processes. This is information is
redundant. So let's show linked libraries only in the worker context, if
haproxy was started also with -W.

This does not need to be backported, as related to the latest master-worker
rework.

src/haproxy.c

@@ -2456,7 +2456,7 @@ static void step_init_2(int argc, char** argv)
 	}
 
 #if defined(HA_HAVE_DUMP_LIBS)
-	if (global.mode & MODE_DUMP_LIBS) {
+	if (global.mode & MODE_DUMP_LIBS && !master) {
 		qfprintf(stdout, "List of loaded object files:\n");
 		chunk_reset(&trash);
 		if (dump_libs(&trash, ((arg_mode & (MODE_QUIET|MODE_VERBOSE)) == MODE_VERBOSE)))