manual : Added a warning against checks at boot time

The booting process has recently been changed so that partitions
which are requested to be checked at mount time with no checker
available, cause a specific user interaction while booting.
The patch warns users against requesting such a check, as there
is no known open-source ntfs file system checker.

src/ntfs-3g.8.in

@@ -375,8 +375,10 @@ to be the owner of all files:
 .B ntfs-3g /dev/sda5 /home/user/mnt \-o ro,uid=1000
 .sp
 .RE
-/etc/fstab entry for the above:
+/etc/fstab entry for the above (the sixth and last field has to be zero to
+avoid a file system check at boot time) :
 .RS
+.sp
 .B /dev/sda5 /home/user/mnt ntfs\-3g ro,uid=1000 0 0
 .sp
 .RE