SSP cases get rcp45 anomalies

[samsrabin]

Brief summary of bug

When setting up an SSP case with anomaly forcings requested, by default it gets rcp45 anomalies, regardless of SSP requested.

This is probably an external thing, but @wwieder suggested I raise it here first.

General bug information

CTSM version you are using: ctsm5.1.dev159

Does this bug cause significantly incorrect results in the model's science? Yes, if not manually corrected.

Configurations affected: Probably any SSP compset where anomaly forcings are created. Tested with ssp245, ssp370, and ssp585.

Important details of your setup / configuration so we can reproduce the bug

Tested on Derecho with the bash script /glade/u/home/samrabin/ctsm5.1.dev159/setup_case.sh, which

1. takes one argument, of ssp number (e.g., 245);
2. sets up a test case with compset using that SSP;
3. specifies anomaly_forcing = 'Anomaly.Forcing.Temperature' in user_nl_datm,
4. prints the name of that case, and
5. prints the datafile associated with Anomaly.Forcing.Temperature in CaseDocs/datm.streams.xml.

Important output or errors that show the problem

No matter what SSP is specified, datm.streams.xml has this:

  <stream_info name="Anomaly.Forcing.Temperature">
   <taxmode>cycle</taxmode>
   <tintalgo>nearest</tintalgo>
   <readmode>single</readmode>
   <mapalgo>bilinear</mapalgo>
   <dtlimit>1.5</dtlimit>
   <year_first>2006</year_first>
   <year_last>2300</year_last>
   <year_align>2006</year_align>
   <vectors>null</vectors>
   <meshfile>/glade/campaign/cesm/cesmdata/inputdata/atm/datm7/anomaly_forcing/domain.permafrostRCN_P2.c2013.nc</meshfile>
   <lev_dimname>null</lev_dimname>
   <datafiles>
      <file>/glade/campaign/cesm/cesmdata/inputdata/atm/datm7/anomaly_forcing/af.tas.ccsm4.rcp45.2006-2300.nc</file>
   </datafiles>
   <datavars>
      <var>tas   Sa_tbot_af</var>
   </datavars>
   <offset>0</offset>
  </stream_info>