fix no-exceptions build with invariant checks

git-svn-id: http://libtorrent.googlecode.com/svn@10192 f43f7eb3-cfe1-5f9d-1b5f-e45aa6702bda
merged no-exception handling fix from RC_0_16

git-svn-id: http://libtorrent.googlecode.com/svn@10193 f43f7eb3-cfe1-5f9d-1b5f-e45aa6702bda
fix no-exception build

git-svn-id: http://libtorrent.googlecode.com/svn@10194 f43f7eb3-cfe1-5f9d-1b5f-e45aa6702bda