Added module compilers so that no CompilerSpecError is thrown

var/spack/mock_configs/site_spackconfig/compilers.yaml

@@ -5,8 +5,18 @@ compilers:
       cxx: /path/to/clang++
       f77: None
       fc: None
+      modules: None
     gcc@4.5.0:
       cc: /path/to/gcc
       cxx: /path/to/g++
       f77: /path/to/gfortran
       fc: /path/to/gfortran
+      modules: None
+    gcc@5.2.0:
+        cc: cc
+        cxx: CC
+        f77: ftn
+        fc: ftn
+        modules:
+        - PrgEnv-gnu
+        - gcc/5.2.0