rgw: add swift task
rgw: add swift task

still not completely working (for some reason it skips all the tests)

tchaikov/teuthology,caibo2014/teuthology,caibo2014/teuthology,dmick/teuthology,SUSE/teuthology,zhouyuan/teuthology,yghannam/teuthology,SUSE/teuthology,michaelsevilla/teuthology,ktdreyer/teuthology,ivotron/teuthology,tchaikov/teuthology,zhouyuan/teuthology,yghannam/teuthology,t-miyamae/teuthology,dmick/teuthology,michaelsevilla/teuthology,dreamhost/teuthology,ktdreyer/teuthology,robbat2/teuthology,t-miyamae/teuthology,dreamhost/teuthology,ceph/teuthology,robbat2/teuthology,SUSE/teuthology,ivotron/teuthology,dmick/teuthology,ceph/teuthology