Replace readdir_r to readdir to fix build error
[Problem] After update tool chain to GCC6, 'readdir_r is deprecated' build error happen
'readdir_r' is deprecated because of below reasons.
* On systems where NAME_MAX is undefined, calling readdir_r() may be
unsafe because the interface does not allow the caller to specify
the length of the buffer used for the returned directory entry.
* On some systems, readdir_r() can't read directory entries with
very long names. When the glibc implementation encounters such a
name, readdir_r() fails with the error ENAMETOOLONG after the
final directory entry has been read. On some other systems,
readdir_r() may return a success status, but the returned d_name
field may not be null terminated or may be truncated.
Change-Id: Iaeabf4b09ab77dfedbc161c725c27a39ec4325c2
Signed-off-by: jiyong.min <jiyong.min@samsung.com>