vyatta-cluster: wait for link up on clustering for up to 10 seconds

If the interfaces involved in a cluster are slow to either gain carrier
or show as link up during boot, the cluster configuration will fail to
load.  Add a delay of up to 10 seconds for this to occur, retesting
every second for a change in carrier / link status.

Bug #243 http://bugzilla.vyos.net/show_bug.cgi?id=243

lib/Vyatta/Cluster/Config.pm

@@ -174,9 +174,17 @@ sub check_interfaces {
         next if ($exist_only);
 
         my $link = `ip link show $_ | grep $_`;
-        if (($link =~ /NO-CARRIER/) || !($link =~ /,UP/)) {
-            return "interface $_ is not connected";
+        my $link_test = 0;
+
+        while (($link =~ /NO-CARRIER/) || !($link =~ /,UP/)) {
+            $link_test++;
+            sleep(1);
+            $link = `ip link show $_ | grep $_`;
+            if ($link_test >= 10) {
+                return "interface $_ is not connected";
+            }
         }
+
         system("ip addr show dev $_ |grep 'inet ' |grep -q 'scope global'");
         if ($? >> 8) {
             return "interface $_ is not configured";