Change cuda_correlator -n option to -f
Change cuda_correlator -n option to -f

The -n option (shorthand for "-o 0") has been replaced by a
"-f FINAL_SYNC_OP" option.  This allows the user to specify which sync
operation to perform on the final call.  Used mainly for debugging and
timing analysis.  The final sync operation still defaults to
SYNCOP_DUMP.

GPU-correlators/xGPU,GPU-correlators/xGPU,GPU-correlators/xGPU