remove duplicate big-lebowski/the_dude.gif

big-lebowski/no-huh-uh.gif
![big-lebowski/no-huh-uh.gif](https://raw.github.com/jglovier/gifs/gh-pages/big-lebowski/no-huh-uh.gif)
big-lebowski/the_dude.gif
![big-lebowski/the_dude.gif](https://raw.github.com/jglovier/gifs/gh-pages/big-lebowski/the_dude.gif)