Add missing #pragma warning(pop) in Boost.Function.
Merged revisions 53694 via svnmerge from https://svn.boost.org/svn/boost/trunk
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r53694 | danieljames | 2009-06-06 16:31:47 +0100 (Sat, 06 Jun 2009) | 1 line
Add missing #pragma warning(pop). Fixes #2767.