Fix SVACE defect in IoT.js (fs.scandir)

[Philippe Coval]

While updating IoT.js in Tizen:RT,
I noticed this downstream patch,
it still applies to current version of IoT.js
so I am forwarding it upstream in libtuv.

To help tracking I am adding references to this changes.

Author: Sanggyu Lee <sg5.lee@samsung.com>
Bug-TizenRT: Samsung/TizenRT#2018
Cc: @juitem
Cc: @glistening
Change-Id: I16cbca383d4e5a7a8cc36eace93999a622f19adc
Forwarded: Samsung#122
Origin: Samsung/TizenRT#744
libtuv-DCO-1.0-Signed-off-by: Philippe Coval philippe.coval@osg.samsung.com

src/unix/fs.c

@@ -407,6 +407,12 @@ static ssize_t uv__fs_scandir(uv_fs_t* req) {
       cnt++;
   }
 
+  if (cnt > 0 && dents == NULL) {
+      closedir(dir);
+      cnt = -1;
+      goto error;
+  }
+
   /* Allcoate memory for the directory entries. */
   dents = (uv__dirent_t**) malloc(sizeof (uv__dirent_t*) * cnt);