Some of these parameters are superfluous, and they give a warning when the program is run:
```
Config results with N_PHOTONS = 1000000
/data2/home/mjarvis/lib/python2.7/site-packages/galsim/utilities.py:563: UserWarning: Overriding random_seed in config with input kwarg value 111333555
  'Overriding random_seed in config with input kwarg value '+str(random_seed))
/data2/home/mjarvis/lib/python2.7/site-packages/galsim/utilities.py:588: UserWarning: Overriding pixel_scale in config with input kwarg value 0.27
  'Overriding pixel_scale in config with input kwarg value '+str(pixel_scale))
/data2/home/mjarvis/lib/python2.7/site-packages/galsim/utilities.py:600: UserWarning: Overriding size in config with input kwarg value 48
  'Overriding size in config with input kwarg value '+str(size))
```
Should remove the duplicated values in either of the two places it is set, so these warnings don't get emitted.