JGit cache bug

This is fun... ~

I cannot figure why things don't work with Patch #4? We are not
even multithreaded.

This is related to trying to fix http://code.google.com/p/egit/issues/detail?id=79 which is related to all
sorts of NPE problems that may occur in Eclipse when working with
EGit and C/msysgit in parallell.

Platform info:

# java version
java version "1.6.0_0"
IcedTea6 1.3.1 (6b12-0ubuntu6.4) Runtime Environment (build 1.6.0_0-b12)
OpenJDK Server VM (build 1.6.0_0-b12, mixed mode)

# uname -a
Linux sleipner 2.6.27-14-generic #1 SMP Wed Apr 15 18:59:16 UTC 2009 i686 GNU/Linux

I've tried to insert GC and sleep calls.

-- robin