Delete and Rename Repository usually fail

Originally reported on Google Code with ID 10

```
The JGit servlet in 1.0.0 is not properly closing a packfile.  Because it does not properly
close the file the repository can not be deleted or renamed without stopping gitblit.

I am trying to track down the bug in JGit to submit to the JGit team.
```

Reported by `James.Moger` on 2011-07-09 01:21:13
