MPAS-A Pertlim usage is only implemented for ideal initial states

[patcal]

What happened?

Adding initial state perturbations is not implemented when reading initial values via ncdata.

What are the steps to reproduce the bug?

Specify an initial values dataset via ncdata, run 5 day tests with pertlim=0, and with pertlim=1.e-14, and then compare the results to see that they are equal.

What CAM tag were you using?

cam6_3_160

What machine were you running CAM on?

CISL machine (e.g. cheyenne)

What compiler were you using?

Intel

Path to a case directory, if applicable

No response

Will you be addressing this bug yourself?

Yes

Extra info

Correcting this to add perturbations to the initial theta values only requires a few lines of code. The PR to add the changes will be implemented for the most recent cam tag: cam6_4_016