First: I do not think so that Canon reduced the price just because they do not selling lenses. To prove that, simply the Canon EF 70-200mm f/2.8L IS II USM Lens went up from $2199 to be $2499.
Second: I post a comment of Canon FB and they respond me by this:
It's on sale right now at the Canon Online Store for $879.99.
This offer is only for a limited time, ending Sunday, September 15, 2013, after which time the lens will go back to its regular price of $1179.00. You can find out more about this great deal at http://bit.ly/15vZF8y
Now, Canon still showing the price as $879.99, BUT, it is out of stock!
I think the price will goes up soon to what it was before in all Canon Dealers. I bought one LIKE NEW for $600 with original box. I will wait until it will goes up and then sell it easy for $850