ssa.c: Rejoin if IBV_EVENT_CLIENT_REREGISTER is recieved.
ssa.c, common.h: Add log_data1 buffer.

 It will be used for log printing where two gids should be
 printed.
ssa.c, core.c: Add parent_gid field to join query.
ssa.c: Add parent's node type to struct ssa_info_record.