ext3: Fix duplicate entries returned from getdents() system call

Fix a regression caused by commit 6a897cf4, "ext3: fix ext3_dx_readdir
hash collision handling", where deleting files in a large directory
(requiring more than one getdents system call), results in some
filenames being returned twice.  This was caused by a failure to
update info->curr_hash and info->curr_minor_hash, so that if the
directory had gotten modified since the last getdents() system call
(as would be the case if the user is running "rm -r" or "git clean"),
a directory entry would get returned twice to the userspace.

This patch fixes the bug reported by Markus Trippelsdorf at:
http://bugzilla.kernel.org/show_bug.cgi?id=11844

Signed-off-by: "Theodore Ts'o" <tytso@mit.edu>
Tested-by: Markus Trippelsdorf <markus@trippelsdorf.de>