Custom preferences are ignored when the project that provided the web preferences is removed

[JacobKlein]

Custom preferences are ignored when the project that provided the web preferences is removed

Problem:
Removing the project where the web preferences came from, deletes the global_prefs.xml file, and BOINC then ignores the global_prefs_override.xml file, and uses stock-install preferences.

Expected behavior / Proposed changes:
1) Removing the project where the web preferences came from, should NOT delete global_prefs.xml (since contacting another project recreates it).
2) If global_prefs_override.xml exists, then it should be used for preferences, even if global_prefs.xml is missing

Test scenario / steps:

Project A: The Lattice Project
Project B: ralph@home
Project C: Einstein@Home
"global_prefs.xml" exists and is from Project A
"global_prefs_override.xml" exists and is being used
All 3 projects know about (are synchronized with) Project A's updated settings

Steps:
- Remove/Detach? Project B
"global_prefs.xml" exists and is from Project A
"global_prefs_override.xml" exists and is being used

- Remove/Detach? Project A
"global_prefs.xml" NO LONGER EXISTS
"global_prefs_override.xml" exists, but IS NOT USED
STOCK DEFAULT PREFERENCES are being used

- Contact Project C
"global_prefs.xml" gets re-created (with the note that it is actually from Project A)
"global_prefs_override.xml" is used again

[JacobKlein]

This was originally reported to the Alpha mailing list by Richard Haselgrove. I found the details and steps to reproduce it, and reported those to the list, and also created this ticket.

[davea]

Fixed in 19b8fda