Boinccmd fails with message indicating it can't find the gui_rpc_auth.cfg file.

[gj82854]

Execution of boinccmd fails because it can't find the gui_rpc_auth.cfg file. This has been happening since version 8 of the BOINC client under Linux. This is due to the /etc/boinc-client/config.properties file not being present or it is present but doesn't contain data_dir=/var/lib/boinc as documented in boinc.berkeley.edu/gui_rpc.php

Steps To Reproduce

1. Execute boinccmd --project www.worldcommunitygrid.org update from any directory other than /var/lib/boinc
2. Command will fail with message saying it can't find gui_rpc_auth.cfg

Expected behavior
Command should successfully execute.

Screenshots
boinccmd --project gene.disi.unitn.it/test/ update
Can't get RPC password: gui_rpc_auth.cfg not found. See https://boinc.berkeley.edu/gui_rpc.php
Only operations not requiring authorization will be allowed.
Operation failed: authentication error

System Information

• OS: Linux (Ubuntu and Fedora)
• BOINC Version: 8.0.x (Tested with 8.0.2 and 8.0.4)

Additional context
Add any other context about the problem here.