Remove an old comment that doesn't seem especially useful.

The functions that follow are concerned with various things, of
which the tar format is only one, so this comment doesn't really
seem helpful. The file isn't really divided into sections in the
way that this comment seems to contemplate -- or at least, not
any more.

Patch by me, reviewed by Michael Paquier.

Discussion: http://postgr.es/m/CA+TgmoZ_fFAoU6mrHt9QBs+dcYhN6yXenGTTMRebZNhtwPwHyg@mail.gmail.com

src/backend/backup/basebackup.c

@@ -1467,13 +1467,6 @@ is_checksummed_file(const char *fullpath, const char *filename)
 		return false;
 }
 
-/*****
- * Functions for handling tar file format
- *
- * Copied from pg_dump, but modified to work with libpq for sending
- */
-
-
 /*
  * Given the member, write the TAR header & send the file.
  *