e2undo: fix endian issues

e2undo: fix endian issues

Two new e2undo issues exist in the latest release on big endian
machines.

From sparse check:

undo_io.c:157:26: warning: invalid assignment: |=
undo_io.c:157:26:    left side has type restricted __le32
undo_io.c:157:26:    right side has type int
undo_io.c:161:26: warning: invalid assignment: &=
undo_io.c:161:26:    left side has type restricted __le32
undo_io.c:161:26:    right side has type int

e2undo.c:211:16: warning: cast to restricted __le64
e2undo.c:211:16: warning: cast from restricted blk64_t
e2undo.c:212:16: warning: cast to restricted __le64
e2undo.c:212:16: warning: cast from restricted blk64_t

Addresses-RedHat-Bugzilla: 1344636
Signed-off-by: Eric Sandeen <sandeen@redhat.com>
Signed-off-by: Theodore Ts'o <tytso@mit.edu>