vim-patch:7.4.455

Problem:  Completion for :buf does not use 'wildignorecase'. (Akshay H)
Solution: Pass the 'wildignorecase' flag around.

https://code.google.com/p/vim/source/detail?r=v7-4-455
Merge pull request #1711 from fwalch/vim-7.4.455

vim-patch:7.4.455