Fix issue #4454

[aanbar]

@narfbg I ran into a similar issue, Looking into the diff you provided
#4454 (comment)

I found out that it was actually being reset, As you have to call the initialize method again to give it the urls ...etc

[narfbg]

Nothing in the documentation implies that you can combine config files with additional initialize() calls without resets. That being said, I don't mind this, but you have to find a way to make it work together with #4000 (the patch for that issue causes this one).

P.S.: I find it funny that you've named the branch "pagination-bc-fix"; 12 version later this is anything but a BC fix. :D

[aanbar]

@narfbg
I've never added a class to my pagination links before, that's why I did not notice the difference until now; blame it on bootstrap 4 maybe? :D.
And I don't think that anything related to styling should be reset unless you explicitly want to reset it

I have updated the file to account for the rel attribute