nfsd: don't support msnfs export option

We've long had these pointless #ifdef MSNFS's sprinkled throughout the
code--pointless because MSNFS is always defined (and we give no config
option to make that easy to change).  So we could just remove the
ifdef's and compile the resulting code unconditionally.

But as long as we're there: why not just rip out this code entirely?
The only purpose is to implement the "msnfs" export option which turns
on Windows-like behavior in some cases, and:

	- the export option isn't documented anywhere;
	- the userland utilities (which would need to be able to parse
	  "msnfs" in an export file) don't support it;
	- I don't know how to maintain this, as I don't know what the
	  proper behavior is; and
	- google shows no evidence that anyone has ever used this.

Signed-off-by: J. Bruce Fields <bfields@redhat.com>
diff --git a/include/linux/nfsd/export.h b/include/linux/nfsd/export.h
index 8ae78a6..bd31615 100644
--- a/include/linux/nfsd/export.h
+++ b/include/linux/nfsd/export.h
@@ -35,7 +35,7 @@
 #define NFSEXP_NOHIDE		0x0200
 #define NFSEXP_NOSUBTREECHECK	0x0400
 #define	NFSEXP_NOAUTHNLM	0x0800		/* Don't authenticate NLM requests - just trust */
-#define NFSEXP_MSNFS		0x1000	/* do silly things that MS clients expect */
+#define NFSEXP_MSNFS		0x1000	/* do silly things that MS clients expect; no longer supported */
 #define NFSEXP_FSID		0x2000
 #define	NFSEXP_CROSSMOUNT	0x4000
 #define	NFSEXP_NOACL		0x8000	/* reserved for possible ACL related use */