internal: do not check packages if task buildpackages is found
internal: do not check packages if task buildpackages is found

The buildpackages task is responsible for creating the packages, there
is no point in verifying they are already present.

Signed-off-by: Loic Dachary <b6eae37fc74638590e3f9030895d42446505d41b@dachary.org>

dreamhost/teuthology,dmick/teuthology,SUSE/teuthology,robbat2/teuthology,dmick/teuthology,robbat2/teuthology,ceph/teuthology,ktdreyer/teuthology,dreamhost/teuthology,SUSE/teuthology,caibo2014/teuthology,dmick/teuthology,SUSE/teuthology,ceph/teuthology,caibo2014/teuthology,ktdreyer/teuthology