[cdt-dev] deadlocks

[Elena Laskavaia <elaskavaia@xxxxxxx>]

I get across another dead-lock between jobs and locking 
CProjectDescriptiorManager.
To fix it for good we may need to use eclipse locking which can 
"undeadlock" things, but for now I want to apply simple fix that applied 
to this particular problem 
https://bugs.eclipse.org/bugs/show_bug.cgi?id=241288.

If nobody has any objections I would commit the patch. Technically as 
Doug mentioned in pr, it can create other problems, but I don't think it 
would in this particular case because this method is called without the 
lock most of the time (and this is maybe a reason that it is hard to 
reproduce in practice).