Maint: Clear memory facts now that they are loaded earlier

The previous commit moved the preloading of memory related facts to the
outermost describe block. When the inner describe block tried to preload
the swapencrypted fact, it would fail on non-Darwin systems, because the
stubs where never evaluated.

This commit clears the facts in the inner describe block as is done for
every other platform.
Merge remote-tracking branch 'upstream/stable'

* upstream/stable:
  Maint: Clear memory facts now that they are loaded earlier