qa/common.check: rework _host_to_fqdn()
qa/common.check: rework _host_to_fqdn()

Was failing in CI, especially for continer platforms.

adfernandes/pcp,adfernandes/pcp,adfernandes/pcp,adfernandes/pcp,adfernandes/pcp,adfernandes/pcp,adfernandes/pcp,adfernandes/pcp