ssa.c: Clear event and revent on timer's file descriptor, if setimerfd_settime failed

Pointed-out-by: Hal Rosenstock <hal@mellanox.com>

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