Add comm_init() function

src/sn.c

@@ -45,6 +45,7 @@ static int load_allowed_sn_community(n2n_sn_t *sss, char *path) {
   }
 
   HASH_ITER(hh, sss->communities, s, tmp) {
+    if(s->is_federation) continue;
     HASH_DEL(sss->communities, s);
     if (NULL != s->header_encryption_ctx)
       free (s->header_encryption_ctx);
@@ -89,11 +90,9 @@ static int load_allowed_sn_community(n2n_sn_t *sss, char *path) {
       }
     }
 
-    s = (struct sn_community*)calloc(1,sizeof(struct sn_community));
+    comm_init(s,cmn_str);
 
     if(s != NULL) {
-      strncpy((char*)s->community, cmn_str, N2N_COMMUNITY_SIZE-1);
-      s->community[N2N_COMMUNITY_SIZE-1] = '\0';
       /* loaded from file, this community is unpurgeable */
       s->purgeable = COMMUNITY_UNPURGEABLE;
       /* we do not know if header encryption is used in this community,