Remove zlib copyright notice

Our embedded zlib got removed way back in cc8c6a2.

README.rst

@@ -99,34 +99,6 @@ It also contains the following systemd service:
 ACKNOWLEDGEMENTS
 ================
 
-This distribution contains zlib compression software.  This is:
-
-  Copyright (C) 1995-2002 Jean-loup Gailly and Mark Adler
-
-  This software is provided 'as-is', without any express or implied
-  warranty.  In no event will the authors be held liable for any damages
-  arising from the use of this software.
-
-  Permission is granted to anyone to use this software for any purpose,
-  including commercial applications, and to alter it and redistribute it
-  freely, subject to the following restrictions:
-
-  1. The origin of this software must not be misrepresented; you must not
-     claim that you wrote the original software. If you use this software
-     in a product, an acknowledgment in the product documentation would be
-     appreciated but is not required.
-  2. Altered source versions must be plainly marked as such, and must not be
-     misrepresented as being the original software.
-  3. This notice may not be removed or altered from any source distribution.
-
-  Jean-loup Gailly        Mark Adler
-  jloup@gzip.org          madler@alumni.caltech.edu
-
-  The data format used by the zlib library is described by RFCs (Request for
-  Comments) 1950 to 1952 in the files ftp://ds.internic.net/rfc/rfc1950.txt
-  (zlib format), rfc1951.txt (deflate format) and rfc1952.txt (gzip format).
-
-
 This distribution contains public domain DES software by Richard Outerbridge.
 This is: