configure.py: set optimisation level to -O3
configure.py: set optimisation level to -O3

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