ext3: fix ext3_dx_readdir hash collision handling

This fixes a bug where readdir() would return a directory entry twice
if there was a hash collision in an hash tree indexed directory.

[akpm@linux-foundation.org: coding-style fixes]
Signed-off-by: Eugene Dashevsky <eugene@ibrix.com>
Signed-off-by: Mike Snitzer <msnitzer@ibrix.com>
Signed-off-by: "Theodore Ts'o" <tytso@mit.edu>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>