[RFC] vim-patch:7.4.314

```
Problem:    Completion messages can get in the way of a plugin.
Solution:   Add 'c' flag to 'shortmess' option. (Shougo Matsu)
```

https://code.google.com/p/vim/source/detail?r=4d7af1962d6ce61df65fdc5c86544a61951f9517