Don't fail on unknown nfs mount options. The kernel automatically
adds a few mount options that we don't currently handle, like:
sec=null|sys|krb5..
mountaddr=<ip>
mountproto=tcp|udp
local_lock=none|all|flock|posix
Which causes a simple mount -o remount,rw <mountpoint> to fail.
Signed-off-by: Peter Korsgaard <jacmet@sunsite.dk>
Signed-off-by: Denys Vlasenko <vda.linux@googlemail.com>