Fix ext2fs_extent_get for uninit leaf extents

Fix ext2fs_extent_get for uninit leaf extents

The ext2fs_extent_get() function was not OR-ing together UNINIT
and LEAF flags in the case where an extent was both; so if we
had an extent which was both uniint and leaf, pass1 would bail
out where depth == max_depth but was not marked as leaf, and
e2fsck (from the next branch) would abort with:

e2fsck 1.40.8 (13-Mar-2008)
Pass 1: Checking inodes, blocks, and sizes
Error1: No 'down' extent
Aborted

Also, if the error is encountered again, print the inode number
to aid debugging until it's properly handled, at least.

Signed-off-by: Eric Sandeen <sandeen@redhat.com>
Signed-off-by: "Theodore Ts'o" <tytso@mit.edu>