common: release uv_fs_scandir() array

uv__fs_scandir_cleanup() releases individual directory entries,
but not the container array. This commit frees the array as well.

Fixes: https://github.com/libuv/libuv/issues/873
PR-URL: https://github.com/libuv/libuv/pull/874
Reviewed-By: Ben Noordhuis <info@bnoordhuis.nl>
Reviewed-By: Saúl Ibarra Corretgé <saghul@gmail.com>

src/uv-common.c

@@ -503,6 +503,9 @@ void uv__fs_scandir_cleanup(uv_fs_t* req) {
     (*nbufs)--;
   for (; *nbufs < (unsigned int) req->result; (*nbufs)++)
     uv__fs_scandir_free(dents[*nbufs]);
+
+  uv__fs_scandir_free(req->ptr);
+  req->ptr = NULL;
 }