chg: do not close dir fd while iterating stable

chg: do not close dir fd while iterating

It works so long as the dp is the last entry, but readdir(dp) would fail
with EBADF. Let's not do that and close the dir fd explicitly.

--- a/contrib/chg/chg.c	Tue Nov 03 11:12:25 2020 +0900
+++ b/contrib/chg/chg.c	Tue Nov 03 11:15:50 2020 +0900
@@ -288,7 +288,7 @@
 				         de->d_name);
 				continue;
 			}
-			if (fd_value > STDERR_FILENO) {
+			if (fd_value > STDERR_FILENO && fd_value != dirfd(dp)) {
 				debugmsg("closing fd %ld", fd_value);
 				int res = close(fd_value);
 				if (res) {
@@ -298,6 +298,7 @@
 				}
 			}
 		}
+		closedir(dp);
 	}
 
 	if (putenv("CHGINTERNALMARK=") != 0)