X files factor fixes

Rebased and cleaned version of #63

"It seems as if the method was left over after implementing a comparison using only two digits of the float values for xFilesFactor. This leads to migration of every single whisper file"
believe this should be:
```
print "xFilesFactor: %.2f (wsp file) / %.2f (storage-aggregation.cfg)" % (str(info['xFilesFactor']),str(xFilesFactor))
```
or something like that if that's what's being compared below...