-z no longer in nc, kubernetes tests fail

[concaf]

sudo make clean-all install kubernetes fails like this:

...
...
2ffe575e81f34a672d10cb1d1f9b096cf842e2bc823def2dcf0039d37acaf00d
Usage of loopback devices is strongly discouraged for production use. Either use `--storage-opt dm.thinpooldev` or use `--storage-opt dm.no_warn_on_loop_devices=true` to suppress this warning.
nc: invalid option -- 'z'
Ncat: Try `--help' or man(1) ncat for more information, usage options and help. QUITTING.
...
nc: invalid option -- 'z'
Ncat: Try `--help' or man(1) ncat for more information, usage options and help. QUITTING.
...
nc: invalid option -- 'z'
Ncat: Try `--help' or man(1) ncat for more information, usage options and help. QUITTING.
...
nc: invalid option -- 'z'
Ncat: Try `--help' or man(1) ncat for more information, usage options and help. QUITTING.
...
...

[concaf]

Fails because of https://github.com/projectatomic/adb-tests/blob/master/cdrage-atomicapp-ci/providers/kubernetes.sh#L40

AFAIK, nc does not have -z available after CentOS 6, since openbsd-ncat has been replaced by nmap-ncat which does not have the -z option.

How about scanning ports using nmap?

References: https://bugs.launchpad.net/percona-xtradb-cluster/+bug/1349384

[concaf]

Closed https://github.com/projectatomic/adb-tests/pull/12#issuecomment-191250624