Remove solar_htng_spctrl_scl from aquaplanet use case

[brian-eaton]

What is the feature/what would you like to discuss?

The namelist variable solar_htng_spectrl_scl is set to true in the aquaplanet use case files aquaplanet_cam5.xml and aquaplanet_cam6.xml. This setting is unnecessary since it is the default for cam5 and cam6 which both use RRTMG. If a user tries to run the cam5 or cam6 aquaplanet configurations with RRTMGP instead of RRTMG then the runs fail because
RRTMGP requires solar_htng_spectrl_scl be set to false. If solar_htng_spectrl_scl is removed from the use case files then its value will be set correctly by build-namelist.

Is there anyone in particular you want to be part of this conversation?

No response

Will this change (regression test) answers?

No

Will you be implementing this enhancement yourself?

Yes