replace RuntimeError exception by log message in buildnml

cime_config/buildnml

@@ -78,11 +78,11 @@ def buildnml(case, caseroot, compname):
             buildcpp = import_from_file("buildcpp", cmd)
             _ = buildcpp.buildcpp(case)
         except:
-            raise RuntimeError("CAM's 'buildcpp' script failed to run properly.")
+            logger.warning("     ...cam buildcpp exited with error")
 
     # Verify that we have a config_cache file (generated by the call to buildcpp)
     expect(os.path.isfile(filename),
-           " Missing config_cache.xml - cannot run build-namelist")
+           " Missing CAM's config_cache.xml - cannot run build-namelist")
 
     #--------------------------------------------------------------------
     # Invoke cam build-namelist - output will go in $CASEROOT/Buildconf/camconf

doc/ChangeLog

@@ -3,7 +3,7 @@
 Tag name:
 Originator(s): jedwards, eaton
 Date:
-One-line Summary: fix issue #1108, merge PR#1101
+One-line Summary: fix issues #1108, #1106; merge PR#1101
 Github PR URL: 
 
 Purpose of changes (include the issue number and title text for each relevant GitHub issue):
@@ -17,6 +17,14 @@ Issue #1108 - More robust logic in gw_drag.F90 when deep_scheme='off'
 PR #1101 - improved fix for rh write performance
 - reorder output fields.  Merge Jim's PR into this one.
 
+Issue #1106 - Report an error if a user uses --model_top with anything other than cam7
+- configure reports this error, but the output in the log file gets
+  obscured by a stack traceback issued from buildnml which is not useful.
+  The fix implemented in buildnml replaces the "raise RuntimeError" call in
+  buildcpp by a warning message in the log file.  If a subsequent check for
+  CAM's config_cache.xml file fails, then exection is terminated by a call
+  to the CIME.utils "expect()" routine.
+
 
 
 Describe any changes made to build system:
@@ -39,6 +47,9 @@ List all existing files that have been modified, and describe the changes:
 bld/build-namelist
 . add check to set use_gw_convect_dp=.false. when deep_scheme='off'.
 
+cime_config/buildnml
+. replace RuntimeError exception by message to logger.
+
 src/control/cam_history.F90
 . The variables in the restart history files are reordered so that the nacs
   variables are all written together rather than being next to their