Return a better error to the user when the GPO Portal is offline, and

we cannot get their project list, which causes create_instance to fail.

apt/create_instance.in

@@ -496,7 +496,9 @@ if ($localuser) {
 	#
 	system("$UPDATEGENIUSER -p " . $emulab_user->uid());
 	if ($?) {
-	    fatal("Not a member of any projects");
+	    UserError("Could not get your project membership from your ".
+		      "member authority. It is probably offline, please try ".
+		      "again later.");
 	}
 	
 	# Nonlocal users get the holding project.