Fixed wrong setup for easyvim

I had a lot of trouble getting easymotion to highlight well with the Solarized dark theme in iTerm. I figured out the reason it wasn't working.

The two settings `hl_group_target` and `hl_group_shade` are used to set your easymotion highlight groups.

`ErrorMsg` and `Comment` are [usually preferred](https://github.com/Lokaltog/vim-easymotion/blob/master/doc/easymotion.txt#L1000). They used to default to `EasyMotionTarget` and `EasyMotionShade`( in which case those groups would have to be defined later).

The lines I deleted are kind of useless. Not sure why `hl_group_target` was set to `Question` before. But, since `hl_group_target` was set to the `Question` highlight group, it would never have looked for the `EasyMotionTarget` group. So making it yellow was unnecessary in the first place.