Create environment only if needed

ci/setup_spack.sh

@@ -21,7 +21,10 @@ git -C spack checkout $SPACK_VERSION
 
 echo "Adding spack system config file"
 
-spack/bin/spack env create ${environment}
+if [ ! -e ${SPACK_SYSTEM_CONFIG_PATH}/spack.yaml ]
+then
+  spack/bin/spack env create ${environment}
+fi
 
 for file in mirrors.yaml packages.yaml concretizer.yaml config.yaml spack.yaml packages_stack.yaml
 do