pythonplugin: initialize all scalar fields in constructor
pythonplugin: initialize all scalar fields in constructor

This fixes a number of valgrind diagnostics like
==11466== Conditional jump or move depends on uninitialised value(s)
==11466==    at 0x41F8B0A: PythonPlugin::call(char const*, char const*, boost::python::api::object, boost::python::api::object, boost::python::api::object&) (python_plugin.cc:90)
(this particular one pertained to the field 'reload_on_change' which was
never initialized)

ikcalB/linuxcnc-mirror,mhaberler/machinekit,narogon/linuxcnc,cdsteinkuehler/MachineKit,ianmcmahon/linuxcnc-mirror,bmwiedemann/linuxcnc-mirror,Cid427/machinekit,araisrobo/machinekit,araisrobo/linuxcnc,cnc-club/linuxcnc,strahlex/machinekit,aschiffler/linuxcnc,ArcEye/machinekit-testing,unseenlaser/machinekit,narogon/linuxcnc,cnc-club/linuxcnc,bmwiedemann/linuxcnc-mirror,Cid427/machinekit,cdsteinkuehler/MachineKit,araisrobo/linuxcnc,EqAfrica/machinekit,RunningLight/machinekit,unseenlaser/machinekit,strahlex/machinekit,RunningLight/machinekit,bobvanderlinden/machinekit,ianmcmahon/linuxcnc-mirror,ArcEye/MK-Qt5,ianmcmahon/linuxcnc-mirror,kinsamanka/machinekit,cnc-club/linuxcnc,ianmcmahon/linuxcnc-mirror,narogon/linuxcnc,araisrobo/linuxcnc,kinsamanka/machinekit,EqAfrica/machinekit,ArcEye/MK-Qt5,ArcEye/MK-Qt5,EqAfrica/machinekit,EqAfrica/machinekit,ArcEye/MK-Qt5,RunningLight/machinekit,strahlex/machinekit,mhaberler/machinekit,aschiffler/linuxcnc,ArcEye/machinekit-testing,araisrobo/machinekit,bobvanderlinden/machinekit,unseenlaser/linuxcnc,araisrobo/machinekit,ianmcmahon/linuxcnc-mirror,cnc-club/linuxcnc,cnc-club/linuxcnc,cdsteinkuehler/linuxcnc,cdsteinkuehler/MachineKit,mhaberler/machinekit,bmwiedemann/linuxcnc-mirror,kinsamanka/machinekit,araisrobo/machinekit,bobvanderlinden/machinekit,ArcEye/MK-Qt5,bmwiedemann/linuxcnc-mirror,strahlex/machinekit,bmwiedemann/linuxcnc-mirror,ArcEye/machinekit-testing,strahlex/machinekit,kinsamanka/machinekit,aschiffler/linuxcnc,kinsamanka/machinekit,araisrobo/machinekit,unseenlaser/linuxcnc,unseenlaser/machinekit,bmwiedemann/linuxcnc-mirror,Cid427/machinekit,Cid427/machinekit,EqAfrica/machinekit,RunningLight/machinekit,cnc-club/linuxcnc,cdsteinkuehler/linuxcnc,cdsteinkuehler/MachineKit,ArcEye/machinekit-testing,ikcalB/linuxcnc-mirror,ianmcmahon/linuxcnc-mirror,ikcalB/linuxcnc-mirror,mhaberler/machinekit,cnc-club/linuxcnc,Cid427/machinekit,cdsteinkuehler/MachineKit,mhaberler/machinekit,bmwiedemann/linuxcnc-mirror,bobvanderlinden/machinekit,ikcalB/linuxcnc-mirror,ikcalB/linuxcnc-mirror,araisrobo/linuxcnc,Cid427/machinekit,strahlex/machinekit,kinsamanka/machinekit,unseenlaser/linuxcnc,RunningLight/machinekit,unseenlaser/linuxcnc,ArcEye/MK-Qt5,mhaberler/machinekit,cdsteinkuehler/linuxcnc,mhaberler/machinekit,Cid427/machinekit,unseenlaser/machinekit,strahlex/machinekit,EqAfrica/machinekit,unseenlaser/machinekit,aschiffler/linuxcnc,unseenlaser/linuxcnc,cdsteinkuehler/linuxcnc,cdsteinkuehler/MachineKit,kinsamanka/machinekit,ArcEye/machinekit-testing,aschiffler/linuxcnc,unseenlaser/machinekit,mhaberler/machinekit,cdsteinkuehler/linuxcnc,EqAfrica/machinekit,araisrobo/machinekit,araisrobo/machinekit,RunningLight/machinekit,narogon/linuxcnc,RunningLight/machinekit,ArcEye/machinekit-testing,araisrobo/linuxcnc,narogon/linuxcnc,Cid427/machinekit,ArcEye/machinekit-testing,ArcEye/MK-Qt5,araisrobo/machinekit,ikcalB/linuxcnc-mirror,bobvanderlinden/machinekit,unseenlaser/machinekit,unseenlaser/machinekit,bobvanderlinden/machinekit,bobvanderlinden/machinekit,ikcalB/linuxcnc-mirror,EqAfrica/machinekit,ianmcmahon/linuxcnc-mirror,araisrobo/machinekit,ArcEye/MK-Qt5,ArcEye/machinekit-testing,bobvanderlinden/machinekit,RunningLight/machinekit,cdsteinkuehler/linuxcnc,kinsamanka/machinekit