Low: scheduler: use same default private parameter list as controller

If the controller doesn't find any parameters marked private in resource agent
meta-data, it uses "password", "passwd", and "user" as the default list
(in metadata_cache_update()).

If the scheduler came across a resource operation history entry with no
op-secure-params list, it previously used " passwd password " as the default.

Even though these are two different situations, and the scheduler should only
find that situation in old saved CIBs, use the same default list for
consistency.