Remove special windows headers

These are provided by MSVC 2013 (and newer) or in our
toplevel platform/include/win32 directory

Change-Id: Ie852af827e878dca30dc9534873dc0f60bdbf3de
Reviewed-on: http://review.couchbase.org/34013
Reviewed-by: Trond Norbye <trond.norbye@gmail.com>
Tested-by: Trond Norbye <trond.norbye@gmail.com>