[RFC] vim-patch:7.4.253

```
Problem:  Crash when using cpp syntax file with pattern using external
          match. (Havard Garnes)

Solution: Discard match when end column is before start column.
```

https://code.google.com/p/vim/source/detail?r=4901a36479f200b2e6700ad91c26911d92deb886