NFSD: fix nfsd_minorversion(.., NFSD_AVAIL)

Current code will return 1 if the version is supported,
and -1 if it isn't.
This is confusing and inconsistent with the one place where this
is used.
So change to return 1 if it is supported, and zero if not.
i.e. an error is never returned.

Signed-off-by: NeilBrown <neilb@suse.com>
Signed-off-by: J. Bruce Fields <bfields@redhat.com>

fs/nfsd/nfssvc.c

@@ -167,7 +167,8 @@ nfsd_adjust_nfsd_versions4(void)
 
 int nfsd_minorversion(u32 minorversion, enum vers_op change)
 {
-	if (minorversion > NFSD_SUPPORTED_MINOR_VERSION)
+	if (minorversion > NFSD_SUPPORTED_MINOR_VERSION &&
+	    change != NFSD_AVAIL)
 		return -1;
 	switch(change) {
 	case NFSD_SET: