storage_service: Fix use after free in rebuild
storage_service: Fix use after free in rebuild

streamer is a stack variable, it is gone when the function returns.
Fix it using a shared pointer.

avikivity/scylla,raphaelsc/scylla,scylladb/scylla,kjniemi/scylla,kjniemi/scylla,duarten/scylla,duarten/scylla,scylladb/scylla,raphaelsc/scylla,scylladb/scylla,scylladb/scylla,avikivity/scylla,duarten/scylla,avikivity/scylla,kjniemi/scylla,raphaelsc/scylla