ssa.c: Use -1 rather than 0 as socket id for "fake" ACMs

Signed-off-by: Sasha Kotchubievsky <sashakot@mellanox.com>
Signed-off-by: Hal Rosenstock <hal@mellanox.com>
core.c: Use DB_EPOCH_INVALID rather than 0 in core_extract_db

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