[Manager] Disk tab displays bad data when connecting to new host

[Vulpine05]

Describe the bug
The Manager displays bad data (erroneous or not valid) when connecting to a new BOINC client after disconnecting from one.

Steps To Reproduce

1. Launch BOINC Manager connected to a client.
2. File->Shut down connected client.., then click OK.
3. Connect to new host (I just left these blank so it would reconnect to the local host).
4. See screenshot below to see what is displayed.

Expected behavior
The pie charts should display blank pies, similar to when starting the Manager.

Screenshots

System Information

• OS: Windows 10 Home
• BOINC Version: 7.24.1 alpha testing, but I suspect this is present in earlier versions.

Additional context

1. Once connected to a host, the pie charts will refresh and display the proper information.
2. For what it is worth "used by BOINC" changed while waiting to connect to the new client. The actual value is 9.20 GB before shutting down the client, but as you can see in the screenshot, that changed to 9.15 GB.

[FTang21]

Helllo,

I would like to work on this issue if this bug has not been fixed yet.

[AenBleidd]

@FTang21, sure, go ahead