Documentation/fs/: split txt and source files

Make dnotify_test.c source file and add it to Makefile so that
bitrot can be prevented.

Signed-off-by: Randy Dunlap <randy.dunlap@oracle.com>
Cc: Stephen Rothwell <sfr@canb.auug.org.au>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>

diff --cc Documentation/Makefile
Simple merge

diff --cc Documentation/filesystems/00-INDEX
Simple merge

diff --cc Documentation/filesystems/Makefile
Simple merge

diff --cc Documentation/filesystems/dnotify.txt
Simple merge

diff --cc Documentation/filesystems/dnotify_test.c
Simple merge