loader: fix page fault at /init scan

scandir() syscall can fail returning -1 , if e.g. rootfs was not mounted.
In that case subsequent free() call try to deallocate some garbage pointer
in namelist variable, leading to page faults.

Initialize namelist to nullptr so that free() always gets valid pointer value.

Signed-off-by: Sergiy Kibrik <sergiy.kibrik@globallogic.com>
Message-Id: <1486655734-4431-1-git-send-email-sergiy.kibrik@globallogic.com>

loader.cc

@@ -465,7 +465,7 @@ void* do_main_thread(void *_main_args)
     // Run command lines in /init/* before the manual command line
     if (opt_init) {
         std::vector<std::vector<std::string>> init_commands;
-        struct dirent **namelist;
+        struct dirent **namelist = nullptr;
         int count = scandir("/init", &namelist, NULL, alphasort);
         for (int i = 0; i < count; i++) {
             if (!strcmp(".", namelist[i]->d_name) ||