Fix importlib usage for files with non .py extension

This is a fixup of 241c9484

slapos/recipe/cmmi/__init__.py

@@ -20,7 +20,8 @@ if sys.version_info >= (3, 5):
     # See https://docs.python.org/3/library/importlib.html#importing-a-source-file-directly
     import importlib.util
     def module_from_file_location(name, path):
-        spec = importlib.util.spec_from_file_location(name, path)
+        loader = SourceFileLoader(name, path)
+        spec = importlib.util.spec_from_loader(name, loader)
         module = importlib.util.module_from_spec(spec)
         sys.modules[name] = module
         spec.loader.exec_module(module)