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.

contrib/chg/chg.c

@@ -288,7 +288,7 b' static void execcmdserver(const struct c'
 				         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 b' static void execcmdserver(const struct c'
 				}
 			}
 		}
+		closedir(dp);
 	}
 
 	if (putenv("CHGINTERNALMARK=") != 0)