integration tests: skip criu tests incorrectly

[lifubang]

I noticed that all criu tests skipped when doing integration tests.
Because -n "$var" means the length of "$var" should be greater than 0, and -z "$var" means the length of "$var" should equal to 0.

I don't know whether skipping all integration tests is your intended thought or not?

Signed-off-by: lifubang lifubang@acmcoder.com

[lifubang]

@kolyshkin How about this one. Now, all criu tests has been skipped in CI in other PR.

ok 21 checkpoint and restore # skip test requires criu
ok 22 checkpoint and restore (bind mount, destination is symlink) # skip test requires criu
ok 23 checkpoint and restore (with --debug) # skip test requires criu
ok 24 checkpoint and restore (cgroupns) # skip test requires criu
ok 25 checkpoint --pre-dump (bad --parent-path) # skip test requires criu
ok 26 checkpoint --pre-dump and restore # skip test requires criu
ok 27 checkpoint --lazy-pages and restore # skip test requires criu
ok 28 checkpoint and restore in external network namespace # skip test requires criu
ok 29 checkpoint and restore with container specific CRIU config # skip test requires criu
ok 30 checkpoint and restore with nested bind mounts # skip test requires criu

[kolyshkin]

The bug is introduced by commit 6e1d476; mea culpa.

I am also fixing this in #3367.

[kolyshkin]

LGTM; thanks for catching this!

[kolyshkin]

OK, since this is fixed by #3367 which is already merged, let me close this one.

Thanks, @lifubang!