Fix kernel attr variable.

pym/cl_fill_install.py

@@ -647,6 +647,7 @@ class fillVars(object, glob_attr):
             attr += "domdadm"
         if self.Get('os_install_lvm_set') == 'on':
             attr += "dolvm"
+        return attr
 
     def get_os_install_kernel_resume(self):
         """install kernel resume parameter"""