If Router Solicitation creation fails no longer tries to retry the RS…

… right away (ARMmbed#2655)

On ethernet interface, if RS cannot be created because there is no source route or
no memory no longer tries to retry the RS right away. Retry is made instead using
standard schedule of RS sending.

source/ipv6_stack/protocol_ipv6.c

@@ -323,16 +323,16 @@ static void ipv6_nd_bootstrap(protocol_interface_info_entry_t *cur)
             break;
 
         case IPV6_ROUTER_SOLICATION:
-            tr_debug("Waiting for ICMPv6 Router Advertisement");
             if (ipv6_nd_rs(cur)) {
+                tr_debug("Waiting for ICMPv6 Router Advertisement");
                 if (cur->ipv6_configure->routerSolicationRetryCounter != ROUTER_SOL_MAX_COUNTER) {
                     cur->ipv6_configure->routerSolicationRetryCounter++;
                 }
-                cur->ipv6_configure->ND_TIMER = (cur->ipv6_configure->routerSolicationRetryCounter * 25);
-
-            } else {
-                cur->ipv6_configure->ND_TIMER = 1;
             }
+            if (cur->ipv6_configure->routerSolicationRetryCounter == 0) {
+                cur->ipv6_configure->routerSolicationRetryCounter++;
+            }
+            cur->ipv6_configure->ND_TIMER = (cur->ipv6_configure->routerSolicationRetryCounter * 25);
             break;
 
         case IPV6_GP_GEN: