Expansion the correct map before testing bits

We hit some quite uncommon crash in our OBS setup where bssolv was
trying to test a bit in a map of size 0. Inspection of the code showed
that while it tried to expand the map to a correct size before the test,
the map it actually expanded wasn't the one it was testing for..
Merge pull request #2 from sjoerd-ccu/master

Expansion the correct map before testing bits