Split conditions in worker pool
Split conditions in worker pool

This patch splits the single threading.Condition object used in the
worker pool for synchronization into three.

- worker_to_pool: Notified if a worker wants to notify the pool
- pool_to_worker: Notified if the pool wants to notify a single
  or all workers
- pool_to_pool: Used for synchronization in Quiesce

Reviewed-by: ultrotter


ganeti/ganeti,apyrgio/snf-ganeti,andir/ganeti,leshchevds/ganeti,onponomarev/ganeti,grnet/snf-ganeti,andir/ganeti,andir/ganeti,ganeti/ganeti,yiannist/ganeti,yiannist/ganeti,mbakke/ganeti,leshchevds/ganeti,bitemyapp/ganeti,ganeti-github-testing/ganeti-test-1,yiannist/ganeti,ganeti/ganeti,ganeti-github-testing/ganeti-test-1,dimara/ganeti,dimara/ganeti,bitemyapp/ganeti,apyrgio/ganeti,apyrgio/ganeti,onponomarev/ganeti,apyrgio/snf-ganeti,leshchevds/ganeti,grnet/snf-ganeti,mbakke/ganeti,mbakke/ganeti