SENS_TEMP isn't computed for compressible flow problems.

[WallyMaier]

Describe the bug When running discrete adjoint, either through the discrete_adjoint.py script, or manually, the SENS_TEMP parameter that is computed is always 0.0 (or 1e-alot) when looking at a Cl or CD functional. These values are non-physical. I haven't checked the other values (SENS_AOA, PRESS, MACH).

I imagine this is caused by a "break" in the recording tape for the DA. Though I haven't found anything yet.

This issue is present in the develop branch.

Bug report checklist

• [ X] Consulting the build instructions (https://su2code.github.io/docs_v7/Build-SU2-Linux-MacOS/).
• [ X] Looking for similar problems on GitHub or CFD-Online (https://www.cfd-online.com/Forums/su2/).
• [ X] Updating to the newest version of SU2 (either develop, master, or the pre-built executables https://su2code.github.io/download.html).

Desktop (please complete the following information):

• OS: [e.g., Linux (Redhat 6.6)]
• C++ compiler and version: [e.g., g++ (GCC) 4.8.5]
• MPI implementation and version: [e.g., OpenMPI 3.0.0]
• SU2 Version: [e.g., v6.2.0]