du close handle before exiting

[Loganaden Velvindron]

In du.c, fts_close() is missing before exit.
fts_close() may also return -1 on hitting an
error.

Index: usr.bin/du/du.c
===================================================================
RCS file: /cvs/src/usr.bin/du/du.c,v
retrieving revision 1.23
diff -u -p -r1.23 du.c
--- usr.bin/du/du.c     27 Apr 2011 07:52:11 -0000      1.23
+++ usr.bin/du/du.c     31 Dec 2011 16:29:26 -0000
@@ -202,6 +202,10 @@ main(int argc, char *argv[])
                }
        if (errno)
                err(1, "fts_read");
+       
+       if (fts_close(fts) == -1)
+               err(1, "fts_close");
+       
        if (cflag) {
                prtout((quad_t)howmany(totalblocks, blocksize), "total", hflag);
        }