qa: cp run_xfstests.sh run_xfstests-obsolete.sh

run_xfstests.sh is going to be updated in the next commit to be able to
drive newer xfstests.  Among other things, the new xfstests proper
doesn't support listing tests in ranges, which is what the qemu tests
(run_xfstests_qemu.sh) rely on.  So keep a copy of the old
run_xfstests.sh around until the qemu vm image is regenerated and the
up-to-date exclusion list for its kernel is shaken out.

Signed-off-by: Ilya Dryomov <ilya.dryomov@inktank.com>
qa: catch up with xfstests changes

Back in 2013 xfstests were rearranged, which also changed the way
./check parses test lists.  Catch up with those changes.  As tests can
no longer be listed in ranges, maintain tests that we want to skip in
a global (-E) expunge file.  The list of tests we skip is much shorter,
as most of the tests we skipped previously appeared to pass, but we can
always grow it later.

Two new option flags were added: -r to randomize test order, -x to
enable the use of the expunge file.

Fixes: http://tracker.ceph.com/issues/6385

Signed-off-by: Ilya Dryomov <ilya.dryomov@inktank.com>