networkstatus_nickname_is_unnamed() can get ripped out

  /* Is it marked as owned-by-someone-else? */
  if (networkstatus_nickname_is_unnamed(nickname)) {
    log_info(LD_GENERAL, "The name %s is listed as Unnamed: there is some "
             "router that holds it, but not one listed in the current "
             "consensus.", escaped(nickname));
    return NULL;
  }

The Unnamed flag is long gone from the world, now that proposal 235 has been merged. So we can simplify node_get_by_nickname() by getting rid of this function, plus the discussions about the Named flag.

If we want to get adventuresome, I also see

    int *named_flag; /* Index of the flag "Named" for votes[j] */
    int *unnamed_flag; /* Index of the flag "Unnamed" for votes[j] */

in networkstatus_compute_consensus(). And more generally,

$ grep Named *.c
circuitbuild.c: * If <b>verbose_names</b> is false, give nicknames for Named routers and hex
dirserv.c:/*                 1  Historically used to indicate Named */
dirvote.c:    int *named_flag; /* Index of the flag "Named" for votes[j] */
dirvote.c:        if (!strcmp(fl, "Named"))
dirvote.c:    /* Named and Unnamed get treated specially */
dirvote.c:        if (!strcmp(fl, "Named")) {
networkstatus.c: * nickname, but the Named flag isn't set for that router. */
nodelist.c: * nickname, but the Named flag isn't set for that router. */
nodelist.c:                 "but none is listed as Named in the directory consensus. "
routerparse.c:      else if (!strcmp(tok->args[i], "Named"))