bootstrap: Fix the spelling of README.md (again) and get a new GnuTLS

bootstrap: Fix the spelling of README.md (again) and get a new GnuTLS

We re-run ./bootstrap/template.py --render to get a new GnuTLS on Fedora 32

This was missed with 7dc535995bbdb42b1b053c22acff5978cb5da516
and so caused e0e51632cf77be439ebcbcba025a42e8558fa824 to
break the sha1sum and so require 7077be01a3cc860ce1fcfafd9e5028829f0c1887
to fix it.

The sha1sum changes because we fixed the bug about the spelling of
README.md, which is helpful because otherwise we would not get a
new image.

This provides a GnuTLS 3.6.15 so that we still test using GnuTLS's
gnutls_aead_cipher_encryptv2() for the SMB encryption codepath.

BUG: https://bugzilla.samba.org/show_bug.cgi?id=14399

Signed-off-by: Andrew Bartlett <abartlet@samba.org>
Reviewed-by: Andreas Schneider <asn@samba.org>