net: Fix do_set_link() return type

do_set_link() returns int, but Monitor handler functions should
always return void.

Signed-off-by: Luiz Capitulino <lcapitulino@redhat.com>
Signed-off-by: Anthony Liguori <aliguori@us.ibm.com>
Message-Id: 
diff --git a/net.c b/net.c
index b5e8c9f..1b531e7 100644
--- a/net.c
+++ b/net.c
@@ -2905,7 +2905,7 @@
     }
 }
 
-int do_set_link(Monitor *mon, const char *name, const char *up_or_down)
+void do_set_link(Monitor *mon, const char *name, const char *up_or_down)
 {
     VLANState *vlan;
     VLANClientState *vc = NULL;
@@ -2918,7 +2918,7 @@
 
     if (!vc) {
         monitor_printf(mon, "could not find network device '%s'", name);
-        return 0;
+        return;
     }
 
     if (strcmp(up_or_down, "up") == 0)
@@ -2931,8 +2931,6 @@
 
     if (vc->link_status_changed)
         vc->link_status_changed(vc);
-
-    return 1;
 }
 
 void net_cleanup(void)