remove wgrib2 entry for grib-util module

[AlexanderRichert-NOAA]

Summary

grib-util has a module config entry that adds a (non-existent) wgrib2 executable. This should not be defined there.

Testing

none (no such executable exists)

Applications affected

none

Systems affected

none

Dependencies

none

Issue(s) addressed

Fixes NOAA-EMC/NCEPLIBS-grib_util#312

Checklist

• This PR addresses one issue/problem/enhancement, or has a very good reason for not doing so.
• These changes have been tested on the affected systems and applications.
• All dependency PRs/issues have been resolved and this PR can be merged.

[climbfuji]

@AlexanderRichert-NOAA Do you want to merge this into the release branch instead of develop?

[AlexanderRichert-NOAA]

Closing this in favor of #1049, then we can merge release/1.7.0 in one go later on.