pbulk: What can I expect from reuse_scan_results?

[Matthias Petermann <mp%petermann-it.de@localhost>]

Hello together,

I have another question that is burning on my nails. The scan phase of 
pbulk takes quite a long time for me. So that it goes faster with a 
potential repetition of the build, I have set reuse_scan_results=yes in 
the configuration.

On retry, it then even prints out that the scan-results are being reused:

```
# /usr/pbulk/bin/bulkbuild
Warning: All log files of the previous pbulk run will be
removed in 5 seconds. If you want to abort, press Ctrl-C.
Reusing old scan results
Using old scan results from /mnt/bulklog.old/meta/pscan
Scanning...
...............
```

However, it takes the same amount of time as without reuse, and the 
output on the terminal is the same as the previous run. Is this normal 
behavior, and if so - what can I generally expect from reuse_scan_results?

Kind regards
Matthias