Fix false color mesoscale images

Occasionally goesdump attempts to generate a false color mesoscale but color is not applied to the entire image: https://wx-star.s3.amazonaws.com/goes/hrit/2018/2018-01-17/CMI%20Products/Mesoscale/GOES-16/False%20Color/G16-Mesoscale-FSCLR-1516204796-2018-01-17T1559Z-watermark-size100.png

This should be fixed or disabled altogether.