Given recent elections we need to build a higher wall to keep the
government out of our documents, and we will make the government
pay for it.

These iteration counts were considered appropriate a decade ago.

http://security.stackexchange.com/questions/3959/recommended-of-iterations-when-using-pkbdf2-sha256

We get similar numbers on SandyBridge-E desktop and Haswell i7-4600U laptop:
* with 10k iterations ~20 msec per derivation
* with 100k iterations ~195 msec per derivation
* with 150k iterations ~290 msec per derivation

We can't go too high though because in ODF every package stream gets
its own derived key with a different salt, so a document with embedded
images may need a lot of these.

Change-Id: I6894e71ed399f8c340eff97a9191c8d8419789a6