After commit 21680809, which converted SfxInPlaceClientList to
a vector, the class name is out of whack. There is no need for
SfxInPlaceClientList, just use std::vector, also renamed the
variables that use the class.

Change-Id: I9f0c8d5800376617ac29fbe7da140af2703c0de7
Reviewed-on: https://gerrit.libreoffice.org/46631Tested-by: Jenkins <ci@libreoffice.org>
Reviewed-by: Noel Grandin <noel.grandin@collabora.co.uk>