VCH Creation Log APIs: simplify getAllLogFilePaths

[zjs]

See #6665 (comment):

If you look at the implementation of helper.Ls it would be trivial to change it so that you can actually provide a pattern instead of a static name. There is already a MatchPattern defined as part of the search spec.
That would basically eliminate the need for this function.

[andrewtchin]

deferrable, removed from release 1.3