re PR c++/43069 (ICE: tree check: expected tree that contains 'decl minimal' structure, have 'overload' in set_decl_namespace, at cp/name-lookup.c:3105)

	PR c++/43069
	* name-lookup.c (set_decl_namespace): Don't copy DECL_CONTEXT if the
	decl we looked up doesn't match.

From-SVN: r156841