xfs: test for fixing wrong root inode number in dump

xfs: test for fixing wrong root inode number in dump

Test '-x' option of xfsrestore. With this option, a wrong root inode
number in a dump file is corrected. A root inode number can be wrong
in a dump created by problematic xfsdump (v3.1.7 - v3.1.9) with
bulkstat misuse. In this test, a corrupted dump file is created by
overwriting a root inode number in a header.

Reviewed-by: Darrick J. Wong <djwong@kernel.org>
Signed-off-by: Hironori Shiina <shiina.hironori@fujitsu.com>
Signed-off-by: Zorro Lang <zlang@kernel.org>