Fix consistency check for stopped tasks (#197)
Fix consistency check for stopped tasks (#197)

In occasional cases, it might happen that invalidated world got
marked as stopped before, while we try set it as paused, which
is not a valid transition.
dLobatog/dynflow,Dynflow/dynflow,Dynflow/dynflow,adamruzicka/dynflow,Dynflow/dynflow,dLobatog/dynflow,adamruzicka/dynflow,adamruzicka/dynflow,dLobatog/dynflow,Dynflow/dynflow,adamruzicka/dynflow,dLobatog/dynflow