Revert "minor, make /v0/series/XXX return the contents of the super file"

This reverts commit 2a74c7d6353a96728153eeb618893a241d1d334d.
Merge branch 'core/gandalfd'

* core/gandalfd:
  Revert "minor, make /v0/series/XXX return the contents of the super file"
  minor, make /v0/series/XXX return the contents of the super file
  minor, open lateglu files through mmapat_fn()