suite.py: must pass at least once through the backtrack loop
suite.py: must pass at least once through the backtrack loop

Changing the default of newest to '0' meant that the combined
loop which handles both backtrack and non-backtrack conditions
was never executing, leading to undefined variables.

Signed-off-by: Dan Mick <b07550071eaa6a9296289c43bbd6c90559196431@redhat.com>

dmick/teuthology,SUSE/teuthology,dmick/teuthology,SUSE/teuthology,ceph/teuthology,ceph/teuthology,ktdreyer/teuthology,dmick/teuthology,ktdreyer/teuthology,SUSE/teuthology