#5966: Account config synchronization fix (for stun)

sflphone-client-gnome/src/actions.c

sflphone-client-gnome/src/config/accountconfigdialog.c

sflphone-client-gnome/src/config/accountlistconfigdialog.c

sflphone-client-gnome/src/config/assistant.c

sflphone-client-gnome/src/dbus/dbus.c

sflphone-client-gnome/src/dbus/dbus.h

sflphone-common/src/managerimpl.cpp

sflphone-common/src/sip/sipaccount.cpp

sflphone-common/src/sip/sipaccount.h