Update Filelock.scpt

Loading icons was causing a stack-over throw errors.
It had worked fine in the original file, but once copying into a 
new one and compiled, caused this code to throw an error:
  display dialog dialogMsg with icon alias ((path to me) & "Contents:Resources:lock.icns" as string)
So all icon related code has been removed.
A visual picture is nice to show lock/unlock/warning states, but not 
as important as the code working.