Fixed header include: should have included <boost/type_traits/cv_traits.hpp>

[SVN r9537]

libs/regex

@@ -1 +1 @@
-Subproject commit c126ed4b870219e06ba690e67da938f393d8d17a
+Subproject commit f5368b76661725c0f6db20e1ba1f62bdff180d79