Hand edited PSy files overwritten by PSyclone step

[MatthewHambley]

PSyclone step takes in algorithm .x90 and transformation script .py. These are hashed and that has is applied to the generated PSy layer .f90. On future incremental builds in which the prerequisite files have not changed they should produce the same hash and therefore not trigger a rebuild, overwriting the PSy file. However hand edits to the PSy file (which do not change its filename) are being overwritten.