gen_conserver_cf.py: Deactivate sol before activating it
Some BMCs have an issue where they randomly drop an active sol session,
and then refuse to start a new one claiming another sol session is
already active. Aftert his, console clients and console log files will
fail to show any console output, and just have a series of errors:
Info: SOL payload already active on another session
Info: SOL payload already active on another session
Info: SOL payload already active on another session
Info: SOL payload already active on another session
To recover, we've had to send an sol deactivate command out-of-band of
conserver so that conserver's next reconnect attempt can succeed. Let's
just teach conserver to send the deactivate command itself before every
reconnect attempt.
