The uninitialized session has no peer associated with it yet. There is
no point sending the failed message when abort the session. Sending the
failed message in this case will send to a peer with uninitialized
dst_cpu_id which will casue the receiver to pass a bogus shard id to
smp::submit_to which cases segfault.
In addition, to be safe, initialize the dst_cpu_id to zero. So that
uninitialized session will send message to shard zero instead of random
bogus shard id.
Fixes the segfault issue found by
repair_additional_test.py:RepairAdditionalTest.repair_abort_test
Fixes#3115
Message-Id: <9f0f7b44c7d6d8f5c60d6293ab2435dadc3496a9.1515380325.git.asias@scylladb.com>