Fix bug in JobEngine where an attempt to restart after stop would trigger an exception because the cancellation source was not recreated.
Fix bug in JobEngine where an attempt to restart after stop would trigger an exception because the cancellation source was not recreated.

M-O-S-E-S/opensim,EriHoss/OpenSim_0.8.2.0_Dev_LibLSLCC,M-O-S-E-S/opensim,TomDataworks/opensim,OpenSimian/opensimulator,M-O-S-E-S/opensim,QuillLittlefeather/opensim-1,OpenSimian/opensimulator,OpenSimian/opensimulator,RavenB/opensim,TomDataworks/opensim,EriHoss/OpenSim_0.8.2.0_Dev_LibLSLCC,QuillLittlefeather/opensim-1,RavenB/opensim,TomDataworks/opensim,TomDataworks/opensim,TomDataworks/opensim,RavenB/opensim,RavenB/opensim,TomDataworks/opensim,QuillLittlefeather/opensim-1,OpenSimian/opensimulator,OpenSimian/opensimulator,M-O-S-E-S/opensim,M-O-S-E-S/opensim,RavenB/opensim,QuillLittlefeather/opensim-1,M-O-S-E-S/opensim,M-O-S-E-S/opensim,QuillLittlefeather/opensim-1,EriHoss/OpenSim_0.8.2.0_Dev_LibLSLCC,EriHoss/OpenSim_0.8.2.0_Dev_LibLSLCC,EriHoss/OpenSim_0.8.2.0_Dev_LibLSLCC,TomDataworks/opensim,RavenB/opensim,OpenSimian/opensimulator,OpenSimian/opensimulator,RavenB/opensim,EriHoss/OpenSim_0.8.2.0_Dev_LibLSLCC,QuillLittlefeather/opensim-1,QuillLittlefeather/opensim-1,EriHoss/OpenSim_0.8.2.0_Dev_LibLSLCC