Added failure checks.

[SVN r754]

test/is_convertible_fail.cpp

@@ -0,0 +1,15 @@
+#include <boost/iterator/iterator_adaptors.hpp>
+#include <boost/static_assert.hpp>
+#include <boost/cstdlib.hpp>
+
+int main()
+{
+  {
+    typedef boost::reverse_iterator<int*>  rev_iter1;
+    typedef boost::reverse_iterator<char*> rev_iter2;
+
+    BOOST_STATIC_ASSERT((boost::is_convertible<rev_iter1, rev_iter2>::value));
+  }
+
+  return boost::exit_success;
+}