Update hoomd.Operations.integrator property setting
Update hoomd.Operations.integrator property setting

Removes obsolete _auto_schedule attribute
Allows setting integrator to `None` when not attached
Fixes bug where new integrator would not necessarily get automatically
attached

joaander/hoomd-blue,joaander/hoomd-blue,joaander/hoomd-blue,joaander/hoomd-blue,joaander/hoomd-blue,joaander/hoomd-blue