samba4: update Linux-specific PLIST entries

from mmoll in #46
I am not adding the SunOS part because the files are in the non-OS specific
PLIST, now (the SunOS entries seem to be duplicated)

net/samba4/PLIST.Linux

@@ -1,6 +1,8 @@
-@comment $NetBSD: PLIST.Linux,v 1.1 2018/09/20 10:40:14 jperkin Exp $
+@comment $NetBSD: PLIST.Linux,v 1.2 2019/04/23 07:42:53 maya Exp $
 lib/libnss_winbind.so.2
 lib/libnss_wins.so
 lib/libnss_wins.so.2
 lib/samba/vfs/btrfs.so
 lib/samba/vfs/fileid.so
+man/man8/vfs_btrfs.8
+man/man8/vfs_fileid.8