Branch b1_8

Branch b1_8
b=19743
i=tappro
i=nathan.rutman,robert.read (non-test part)

Attachment 25260: lfs path2fid.  Add a "path2fid <path>" command to
lfs(1).  Ported from HEAD (Bug 17187 and 19856).

Attachment 25261: lctl getobjversion.  Add a new lctl(8) command,
"getobjversion <fid>", to get the version of an object.  Currently, only
versions of MDT objects can be retrieved.

Attachment 24412: replay-vbr rmultiop.  Make the command sequence an
argument, as required by the new replay-vbr tests.  Fix rmultiop_stop's
return code which would always be zero.

Attachment 25094: replay-vbr tests.  Move rmultiop_{start,stop} to top.
Add a zconf_mount_clients to balance the former zconf_umount_clients.
Add new tests 0* and 2b (2 renamed to 2a).