Fix Boost.Function unit tests for C++0x. Fixes #3012

Based on a patch from Richard Webb. Changed a bit so that it also
works for the Visual C++ 10 beta.

[SVN r54618]

libs/function

@@ -1 +1 @@
-Subproject commit e8247198fa3af8470805bb627f79006612c23d4f
+Subproject commit ae534d73424b93bc1f78bc88e50984bee404013c