test.py: print failed test summary if there are failed tests
test.py: print failed test summary if there are failed tests

Signed-off-by: Botond Dénes <a584fa4d75a0a85d721f44fb6e06315a2853b0b6@scylladb.com>
Message-Id: <3a913b111552276ab94dfb83738244699550f929.1507894597.git.a584fa4d75a0a85d721f44fb6e06315a2853b0b6@scylladb.com>

duarten/scylla,avikivity/scylla,scylladb/scylla,avikivity/scylla,duarten/scylla,scylladb/scylla,scylladb/scylla,avikivity/scylla,duarten/scylla,scylladb/scylla