Ostinato does not automatically re-connect to Drone

[pstavirs]

If Drone is killed by pressing Ctrl-C, Ostinato does not try to reconnect.

This might be expected behaviour - the auto-reconnect is possibly only for unexpected socket closures e.g. drone crashing. Need to check.

[pstavirs]

A little bit of research reveals that currently when the client receives a socket error - QAbstractSocket::RemoteHostClosedError, the client does not attempt a reconnect.

This was added to handle cases where version incompatibility checks fail where we do not want to reconnect.

Also, it seems this same error is received irrespective of how drone exits - intentionally, gracefully or crashes out. This makes it impossible to distinguish between the cases on the client side, unless we add some other mechanism to detect the manner of drone exit.