Close _moniter_workers_thread with other threads.
Close _moniter_workers_thread with other threads.

ContinuumIO/dask,pombredanne/dask,blaze/dask,pombredanne/dask,wiso/dask,mraspaud/dask,jakirkham/dask,clarkfitzg/dask,mrocklin/dask,clarkfitzg/dask,wiso/dask,mraspaud/dask,dask/dask,mrocklin/dask,ContinuumIO/dask,jayhetee/dask,PhE/dask,vikhyat/dask,blaze/dask,gameduell/dask,dask/dask,jcrist/dask,cpcloud/dask,mikegraham/dask,ssanderson/dask,jakirkham/dask,cowlicks/dask,vikhyat/dask,simudream/dask,chrisbarber/dask,jcrist/dask,simudream/dask,PhE/dask,jayhetee/dask,ssanderson/dask