MINOR: mworker: displays a message when a worker is forked

Displays the PID and the relative PID when we fork a new worker.
diff --git a/src/haproxy.c b/src/haproxy.c
index 62b9d1a..cfa740d 100644
--- a/src/haproxy.c
+++ b/src/haproxy.c
@@ -2997,6 +2997,7 @@
 			if (global.mode & MODE_MWORKER) {
 				struct mworker_proc *child;
 
+				qfprintf(stdout, "New worker #%d (%d) forked\n", relative_pid, ret);
 				/* find the right mworker_proc */
 				list_for_each_entry(child, &proc_list, list) {
 					if (child->relative_pid == relative_pid &&