ssa.c: Add reconnection timer to upstream thread

The reconnection timer will be used for rsocket connection recovery.
Now, timeout interval is 0 and the timer is disabled.
For the timer, we use timerfd system calls that deliver the timer
notification via a file descriptor. The file descriptor is monitored
by rpoll function.
The timer descriptor is used in non-blocking mode.
timerfd is implemented in glibc.

Reference: http://man7.org/linux/man-pages/man2/timerfd_create.2.html
Requirements: Linux 2.6.27

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