add a default for the auth server in the PAM config

pam/pam_authclient.c

@@ -62,6 +62,10 @@ static void parse_cfg(int argc, const char **argv, struct cfg *cfg) {
   int i;
 
   memset(cfg, 0, sizeof(struct cfg));
+
+  // Set some defaults.
+  cfg->auth_server = "127.0.0.1:1616";
+
   for (i = 0; i < argc; i++) {
     if (!strcmp(argv[i], "debug")) {
       cfg->debug = 1;