Fix detection of very small filesystems (like tar).
* fs/reiserfs.c (grub_reiserfs_mount): When disk is too small to
contain a ReiserFS, abort with GRUB_ERR_BAD_FS rather than
GRUB_ERR_OUT_OF_RANGE (which made the upper layer think there's
a problem with this disk).
* fs/reiserfs.c (grub_reiserfs_get_key_v2_type): Handle endianness
correctly.
(grub_reiserfs_get_key_offset): Likewise.
(grub_reiserfs_set_key_offset): Likewise.
(grub_reiserfs_set_key_type): Likewise.
(grub_reiserfs_iterate_dir): Return 1 if found, otheriwise 0.
(GRUB_REISERFS_KEYV2_BITFIELD): Undefined. Probably it would be
better to remove the bitfield version completely.
* fs/reiserfs.c (grub_reiserfs_iterate_dir): ENTRY_ITEM must be
allocated from the heap, due to the fshelp implementation.
(grub_reiserfs_dir): Free NODE, due to the same reason.