mizuRoute prealpha/prebeta tests are failing to run because of case of local directory in Externals.cfg

[ekluzek]

Brief summary of bug

The prealpha/prebeta tests for mizuRoute have been failing to run because the local directory is lowercase

components/mizuroute

rather than

components/mizuRoute

General bug information

CESM version you are using: cesm2_3_beta16

Starts when mizuRoute was added into CESM

Machine you are using: derecho

Have you modified the code? (If so, please point us to you changes.): No

Details of bug

One way to see it is to do

./query_testlists --xml-category prebeta | grep mizu

There are two ways to correct it. One is to modify Externals.cfg here in CESM.
The other is to modify BOTH cime and CTSM:

• cime -- modify the directory name COMP_ROOT_DIR_ROF in CIME/data/cesm/config_files.xml
• ctsm -- modify the Externals.cfg there

[ekluzek]

@fischer-ncar let me know if you approve of making this change in CESM, and I'll push a PR here. If you want me to do the other option I'll need to push a change to cime.