[ssa_mad.h, core.c, ssa.c]: Add bad_parent flag to ssa_member_record

If the flag is "true", a node can't establish upstream connection to
current parent and asks the core for a new one.

Signed-off-by: Sasha Kotchubievsky <sashakot@mellanox.com>
Signed-off-by: Hal Rosenstock <hal@mellanox.com>