xfs_logprint: Don't error out after split items lose context

xfs_logprint: Don't error out after split items lose context

xfs_logprint recognizes a "left over region from split log item"
but then expects the *next* op to be a valid start to a new
item.  The problem is, we can split i.e. an xfs_inode_log_format
item, skip over it, and then land on the xfs_icdinode_t
data which follows it - this doesn't have a valid log item
magic (XFS_LI_*) and we error out.  This results in something
like:

  xfs_logprint: unknown log operation type (494e)

Fix this by recognizing that we've skipped over an item and
lost the context we're in, so just continue skipping over
op headers until we find the next valid start to a log item.

Signed-off-by: Eric Sandeen <sandeen@redhat.com>
Reviewed-by: Dave Chinner <dchinner@redhat.com>
Signed-off-by: Dave Chinner <david@fromorbit.com>