colorscheme fixing magic doesn't work for gruvbox

[osfameron]

On Vim 7.4 OSX in Gui. From your post in altercation/solarized#102 I guessed this might fix the issue with gruvbox clobbering syntax highlighting, but doesn't.

Replication 1.

• open a Haskell file foo.hs
• :colo distinguished
• :colo gruvbox
• :colo distinguished # syntax is now mis-highlighted

Replication 2.

• open a Haskell file foo.hs
• Press Fn8 repeatedly. Notice how every colorscheme is highlighted
• Stop pressing Fn8 when you get to gruvbox
• Press Shift+Fn8 to go back to the previous one # syntax is now mis-highlighted

Hope that's useful, please let me know if I can supply any more info.