n-acd: use RFC 5227 timeout for announcements

When doing announcements, use the the timeout specified by RFC
5227. Note that timeout_multiplier might be 0.

This aligns behavior to upstream version of n-acd.

shared/n-acd/src/n-acd.c

@@ -563,7 +563,14 @@ static int n_acd_handle_timeout(NAcd *acd) {
                         return r;
 
                 if (++acd->n_iteration < N_ACD_RFC_ANNOUNCE_NUM) {
-                        r = n_acd_schedule(acd, acd->timeout_multiplier * N_ACD_RFC_ANNOUNCE_INTERVAL_USEC, 0);
+                        /*
+                         * Announcements are always scheduled according to the
+                         * time-intervals specified in the spec. We always use
+                         * the RFC5227-mandated multiplier.
+                         * If you reconsider this, note that timeout_multiplier
+                         * might be 0 here.
+                         */
+                        r = n_acd_schedule(acd, N_ACD_TIMEOUT_RFC5227 * N_ACD_RFC_ANNOUNCE_INTERVAL_USEC, 0);
                         if (r < 0)
                                 return r;
                 }

shared/n-acd/src/n-acd.h

@@ -15,6 +15,8 @@ extern "C" {
 #include <netinet/in.h>
 #include <stdbool.h>
 
+#define N_ACD_TIMEOUT_RFC5227 (UINT64_C(9000))
+
 enum {
         _N_ACD_E_SUCCESS,