sqlite3 often fails on connection with action-cable

[catmando]

sequence goes like this:

system boots
any messages sent are queued in temporary polling connection
action-cable notifies client that we are connected
client notifies server that connection is complete and gets any queued messages
temporary connection is destroyed
the new action-cable connection is established

at the destroy step very often sqlite3 dies with a db locked error
this means that the action action-cable connection (within hyper-operation) never is established.

Solution: on the client poll 10 times every 200 ms then fail.

This will help if there are any other reasons for failure at this stage.