Revert pause/unpause state when host restart

Give following scenario for instance task state
1) start to pause an active instance
2) the nova-compute died because of unexpected situation
3) when nova-compute start again , it's task state is pausing
it should be changed to None because host restarted

Also ,for the paused instance and its state is unpausing,
we need to unpase the instance.

Change-Id: If72a36dafd894ac47c0b255d701a3f9965ff2590
Closes-Bug: #1290639
Merge "Revert pause/unpause state when host restart"