LU-11790 ldiskfs: add terminating u32 when expanding inodes

LU-11790 ldiskfs: add terminating u32 when expanding inodes

In ext4_expand_extra_isize_ea(), we calculate the total size of the
xattr header, plus the xattr entries so we know how much of the
beginning part of the xattrs to move when expanding the inode extra
size.  We need to include the terminating u32 at the end of the xattr
entries, or else if there is uninitialized, non-zero bytes after the
xattr entries and before the xattr values, the list of xattr entries
won't be properly terminated.

Signed-off-by: Li Dongyang <dongyangli@ddn.com>
Change-Id: I247b935b3cf315481dc4658133a7eee02b6350e9
Reviewed-on: https://review.whamcloud.com/33893
Tested-by: Jenkins
Tested-by: Maloo <maloo@whamcloud.com>
Reviewed-by: Yang Sheng <ys@whamcloud.com>
Reviewed-by: Andreas Dilger <adilger@whamcloud.com>
Reviewed-by: Alex Zhuravlev <bzzz@whamcloud.com>