Add a 00-INDEX file to Documentation/sysctl/

Add a 00-INDEX file to Documentation/sysctl/
Signed-off-by: NJesper Juhl <jesper.juhl@gmail.com>
Cc: Rob Landley <rob@landley.net>
Cc: Randy Dunlap <rdunlap@xenotime.net>
Signed-off-by: NAndrew Morton <akpm@linux-foundation.org>
Signed-off-by: NLinus Torvalds <torvalds@linux-foundation.org>

Documentation/sysctl/00-INDEX

+00-INDEX
+	- this file.
+README
+	- general information about /proc/sys/ sysctl files.
+abi.txt
+	- documentation for /proc/sys/abi/*.
+ctl_unnumbered.txt
+	- explanation of why one should not add new binary sysctl numbers.
+fs.txt
+	- documentation for /proc/sys/fs/*.
+kernel.txt
+	- documentation for /proc/sys/kernel/*.
+sunrpc.txt
+	- documentation for /proc/sys/sunrpc/*.
+vm.txt
+	- documentation for /proc/sys/vm/*.