bug#7237: 24.0.50; ls-lisp-emulation has wrong value on MS Windows

[Drew Adams]

`ls-lisp-emulation' should have `MS-Windows' as the default
value on MS Windows.

This variable also affects other settings such as `ls-lisp-ignore-case',
`ls-lisp-dirs-first', and `ls-lisp-verbosity'.  If the default value is
`MS-Windows' then it sets those variables correctly, as follows:

`ls-lisp-ignore-case' should be t
`ls-lisp-dirs-first'  should be t
`ls-lisp-verbosity'   should be (links)

In GNU Emacs 24.0.50.1 (i386-mingw-nt5.1.2600)
 of 2010-09-20 on 3249CTO
Windowing system distributor `Microsoft Corp.', version 5.1.2600
configured using `configure --with-gcc (4.4) --no-opt --cflags
-Ic:/imagesupport/include'