A+C: remove Klaus Post <klauspost@gmail.com>.

The previous commit added Klaus Post in anticipation of landing pull
request #19 (https://github.com/golang/snappy/pull/19). That PR has been
abandoned.

AUTHORS

@@ -11,6 +11,5 @@
 Damian Gryski <dgryski@gmail.com>
 Google Inc.
 Jan Mercl <0xjnml@gmail.com>
-Klaus Post <klauspost@gmail.com>
 Rodolfo Carvalho <rhcarvalho@gmail.com>
 Sebastien Binet <seb.binet@gmail.com>

CONTRIBUTORS

@@ -29,7 +29,6 @@
 Damian Gryski <dgryski@gmail.com>
 Jan Mercl <0xjnml@gmail.com>
 Kai Backman <kaib@golang.org>
-Klaus Post <klauspost@gmail.com>
 Marc-Antoine Ruel <maruel@chromium.org>
 Nigel Tao <nigeltao@golang.org>
 Rob Pike <r@golang.org>