Remove physics actor related race conditions in SetVehicleFlags() and SetPhysicsAxisRotation()
Remove physics actor related race conditions in SetVehicleFlags() and SetPhysicsAxisRotation()

sop.PhysActor can currently become null at any time.

ft-/opensim-optimizations-wip,ft-/arribasim-dev-tests,ft-/opensim-optimizations-wip-extras,rryk/omp-server,RavenB/opensim,ft-/opensim-optimizations-wip-tests,QuillLittlefeather/opensim-1,Michelle-Argus/ArribasimExtract,TomDataworks/opensim,BogusCurry/arribasim-dev,bravelittlescientist/opensim-performance,justinccdev/opensim,OpenSimian/opensimulator,RavenB/opensim,ft-/arribasim-dev-tests,M-O-S-E-S/opensim,justinccdev/opensim,EriHoss/OpenSim_0.8.2.0_Dev_LibLSLCC,ft-/opensim-optimizations-wip,BogusCurry/arribasim-dev,M-O-S-E-S/opensim,QuillLittlefeather/opensim-1,EriHoss/OpenSim_0.8.2.0_Dev_LibLSLCC,M-O-S-E-S/opensim,OpenSimian/opensimulator,ft-/arribasim-dev-extras,M-O-S-E-S/opensim,ft-/arribasim-dev-extras,EriHoss/OpenSim_0.8.2.0_Dev_LibLSLCC,rryk/omp-server,rryk/omp-server,Michelle-Argus/ArribasimExtract,TomDataworks/opensim,ft-/opensim-optimizations-wip,TomDataworks/opensim,M-O-S-E-S/opensim,bravelittlescientist/opensim-performance,Michelle-Argus/ArribasimExtract,ft-/arribasim-dev-extras,ft-/arribasim-dev-tests,QuillLittlefeather/opensim-1,OpenSimian/opensimulator,bravelittlescientist/opensim-performance,TomDataworks/opensim,bravelittlescientist/opensim-performance,ft-/opensim-optimizations-wip-tests,RavenB/opensim,ft-/arribasim-dev-tests,rryk/omp-server,RavenB/opensim,RavenB/opensim,TomDataworks/opensim,justinccdev/opensim,M-O-S-E-S/opensim,QuillLittlefeather/opensim-1,Michelle-Argus/ArribasimExtract,EriHoss/OpenSim_0.8.2.0_Dev_LibLSLCC,ft-/opensim-optimizations-wip-tests,RavenB/opensim,ft-/opensim-optimizations-wip-extras,OpenSimian/opensimulator,Michelle-Argus/ArribasimExtract,QuillLittlefeather/opensim-1,ft-/opensim-optimizations-wip-tests,QuillLittlefeather/opensim-1,rryk/omp-server,bravelittlescientist/opensim-performance,ft-/opensim-optimizations-wip-extras,rryk/omp-server,EriHoss/OpenSim_0.8.2.0_Dev_LibLSLCC,OpenSimian/opensimulator,ft-/opensim-optimizations-wip-extras,OpenSimian/opensimulator,ft-/arribasim-dev-extras,EriHoss/OpenSim_0.8.2.0_Dev_LibLSLCC,BogusCurry/arribasim-dev,QuillLittlefeather/opensim-1,justinccdev/opensim,BogusCurry/arribasim-dev,BogusCurry/arribasim-dev,justinccdev/opensim,ft-/arribasim-dev-tests,ft-/opensim-optimizations-wip,RavenB/opensim,M-O-S-E-S/opensim,bravelittlescientist/opensim-performance,ft-/opensim-optimizations-wip-extras,ft-/arribasim-dev-extras,ft-/arribasim-dev-extras,Michelle-Argus/ArribasimExtract,TomDataworks/opensim,ft-/opensim-optimizations-wip-tests,EriHoss/OpenSim_0.8.2.0_Dev_LibLSLCC,OpenSimian/opensimulator,BogusCurry/arribasim-dev,justinccdev/opensim,TomDataworks/opensim,ft-/arribasim-dev-tests