gdb: Adjust 'scylla lsa' for removal of emergency reserve
gdb: Adjust 'scylla lsa' for removal of emergency reserve

There's no _emergency_reserve any more. Show _free_segments instead.

Message-Id: <00c0f35b0fd1eba1baabdc7cd65cfecb20a3a284@scylladb.com>

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