support for recursive STL containers is not required by the standard.
Boost TR1 containers allow them explicitly though but for some compiler/stl
combinations there are constness issues that prevent the default
assignment operator to work. Adding a small helper function solves
this problem in a clean way.
(cherry picked from commit 58d20429)

Conflicts:
	configmgr/source/partial.hxx

Change-Id: I301765e47db12f3b158d4525e896e090f4b81bbb