update to resolve UnboundLocalError
update to resolve UnboundLocalError

File "/mi-instrument/mi/core/instrument/playback.py", line 381, in main
    if zplsc_reader:
UnboundLocalError: local variable 'zplsc_reader' referenced before assignment
vipullakhani/mi-instrument,renegelinas/mi-instrument,danmergens/mi-instrument,oceanobservatories/mi-instrument,renegelinas/mi-instrument,oceanobservatories/mi-instrument,vipullakhani/mi-instrument,danmergens/mi-instrument