BUG/MEDIUM: remove debugging code from systemd-wrapper

Kristoffer Grönlund reported that after my recent update to the
systemd-wrapper, I accidentely left the debugging code which
consists in disabling the fork :-(

The fix needs to be backported to 1.5 as well since I pushed it
there as well.
(cherry picked from commit a55bbc64d8272e4066a67b6d190ffebaff2b300a)
diff --git a/src/haproxy-systemd-wrapper.c b/src/haproxy-systemd-wrapper.c
index 446f28f..8602881 100644
--- a/src/haproxy-systemd-wrapper.c
+++ b/src/haproxy-systemd-wrapper.c
@@ -70,8 +70,7 @@
 	main_argc = wrapper_argc - 1;
 	main_argv = wrapper_argv + 1;
 
-	//pid = fork();
-	pid=0;
+	pid = fork();
 	if (!pid) {
 		/* 3 for "haproxy -Ds -sf" */
 		char **argv = calloc(4 + main_argc + nb_pid + 1, sizeof(char *));