Update ReflectometryServer/pv_wrapper.py
Update ReflectometryServer/pv_wrapper.py

Co-Authored-By: Thomas Lohnert <d313392a790b47ee2d5b47624f8516e43da0fa36@stfc.ac.uk>
ISISComputingGroup/EPICS-inst_servers,ISISComputingGroup/EPICS-inst_servers