Call Bullet.enable=true multiple times
Call Bullet.enable=true multiple times

The strategy of method aliasing creates stack level too deep errors
because we lost track of the original methods.

I wanted to enable and Bullet only within some of my specs in my test
suite. Then, I did it by setting the attribute accessors
n_plus_one_query_enable, unused_eager_loading_enable,
andcounter_cache_enable. But It should be more clear to user
`Bullet.enable = false` directly.

yakovenkodenis/bullet,flyerhzm/bullet,yakovenkodenis/bullet,dwb/bullet,eileencodes/bullet,danp60/bullet,theass/bullet,sideci-sample/sideci-sample-bullet,flyerhzm/bullet,jay3126/bullet,dwb/bullet,PikachuEXE/bullet,sho-h/brakefast,rstacruz/bullet,sho-h/brakefast,jay3126/bullet,danp60/bullet,eileencodes/bullet,rrosenblum/bullet,hannahbot/bullet,rrosenblum/bullet,sideci-sample/sideci-sample-bullet,rstacruz/bullet,theass/bullet,PikachuEXE/bullet,hannahbot/bullet,flyerhzm/bullet