ssa.c: In ssa_upstream_handle_op, start upstream queries when SSA_MSG_DB_UPDATE msg is received and ssa_db is NULL

Signed-off-by: Hal Rosenstock <hal@mellanox.com>
ssa.c: Eliminate passing SSA DB object in internal prepare and ready messages

Don't have the SSA DB yet to pass (it would be the old/current one and
not the one about to come in and be passed in the update message).

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