[PATCH] Make nsec checking optional

[PATCH] Make nsec checking optional

The nsec field of ctime/mtime is now checked only with -DNSEC defined during
compilation. nsec acts broken since it is stored in the icache but apparently
just gets to zero when flushed to filesystem not supporting it (e.g. ext3),
creating illusions of false changes. At least that's my impression.

Signed-off-by: Petr Baudis <pasky@ucw.cz>