squash! pam: Config file support

Address false positive etc.

cfg.c

@@ -210,7 +210,7 @@ static void cfg_load_buffer(cfg_t *cfg, char *buffer) {
 }
 
 static int cfg_load_defaults(cfg_t *cfg, const char *config_path) {
-  int fd, r;
+  int fd = -1, r;
   size_t fsize;
   char *buffer = NULL;