Canopy moisture content output from GEFSv12 grib2 input has erroneously high canopy water content

[LarissaReames-NOAA]

This issue was noted and fixed by @christinaholtNOAA (and others) in their branch (see commit 11f31c53 in the NCAR fork) by correcting the data in qc_check, but I will instead adjust the input data just after read. This change will be tested with a simple unit test to check that values greater than the max allowed value (0.5) are properly replaced by 0.

[GeorgeGayno-NOAA]

@LarissaReames-NOAA What exactly is the problem with the grib2 data? Does the land mask not match the data? I suggest we make a list (and some graphics) of all the problems with the grib2 data so it can be fixed.

[LarissaReames-NOAA]

@GeorgeGayno-NOAA I believe this is tied to the same issue as the erroneous soil temperature problems that I addressed in my last PR, so it's already in the pipe at NCO to be fixed. However, we'll still need this in place for compatibility with current and older files.