qa: fix cephtool test execution

Due to some bad bash syntax, most of the tests were
not being run during calls with --test-mon/--test-mds,
because only the first item in the array of tests
was used.

The problem was introduced in 6741b71d.

Signed-off-by: John Spray <john.spray@redhat.com>
qa: fix teardown in cephtool's test_mon_mds

This was missing from 17b5fc9a but we didn't notice
because the test wasn't being run by the gitbuilders.

Signed-off-by: John Spray <john.spray@redhat.com>