mdns: suppress a Coverity warning

Coverity:
CID 739612 (#1 of 1): Buffer not null terminated (BUFFER_SIZE)
At (5): Calling strncpy with a source string whose length (4 chars) is
        greater than or equal to the size argument (4) will fail to
        null-terminate "hello->head".

Signed-off-by: Ferry Huberts <[email protected]>

Author: fhuberts

lib/mdns/src/RouterElection.c

@@ -200,7 +200,7 @@ void initTimer (void *foo __attribute__ ((unused))){
   memcpy(&ROUTER_ID, &olsr_cnf->main_addr, sizeof(union olsr_ip_addr));
   hello = (struct RtElHelloPkt *) malloc(sizeof(struct RtElHelloPkt));
   OLSR_PRINTF(1,"initialization running step 1\n");
-  strncpy(hello->head, "$REP", 4);
+  memcpy(hello->head, "$REP", 4);
   if(olsr_cnf->ip_version == AF_INET)
     hello->ipFamily = AF_INET;
   else