Documentation: move locks.txt in filesystems/

This documentation (about file locking) belongs in filesystems/.
Signed-off-by: J. Bruce Fields <bfields@citi.umich.edu>

Documentation/00-INDEX

@@ -230,8 +230,6 @@ local_ops.txt
 	- semantics and behavior of local atomic operations.
 lockdep-design.txt
 	- documentation on the runtime locking correctness validator.
-locks.txt
-	- info on file locking implementations, flock() vs. fcntl(), etc.
 logo.gif
 	- full colour GIF image of Linux logo (penguin - Tux).
 logo.txt

Documentation/filesystems/00-INDEX

@@ -52,6 +52,8 @@ isofs.txt
 	- info and mount options for the ISO 9660 (CDROM) filesystem.
 jfs.txt
 	- info and mount options for the JFS filesystem.
+locks.txt
+	- info on file locking implementations, flock() vs. fcntl(), etc.
 mandatory-locking.txt
 	- info on the Linux implementation of Sys V mandatory file locking.
 ncpfs.txt