s/warnp/warn0/ for NETWORK_STATUS_CONNERR errors.

Originally we could rely on errno being meaningful at this point, but with
the switch to using libcperciva's network_connect there's a possibility of
getting a delayed failure callback since network_connect sometimes queues
an immediate callback rather than making a direct call, in order to avoid
problems with unbounded recursion.

At some point in the future this might change back; libcperciva would need
to save and restore errno appropriately first.  (Junior hacker task!)

lib/netproto/netproto.c

@@ -21,8 +21,8 @@ _netproto_printerr(int status)
 
 	switch (status) {
 	case NETWORK_STATUS_CONNERR:
-		/* Could not connect; error is specified in errno. */
-		warnp("Error connecting to server");
+		/* Could not connect. */
+		warn0("Error connecting to server");
 		break;
 	case NETWORK_STATUS_ERR:
 		/* Error is specified in errno. */