Reset @total_count on #clone

Fixes #565
Mongoid 4.0.0 and later should include Mongoid::Attributes::Dynamic
Regression for paginatable array

Sometimes, we want to make an array just paginatable without changing
its elements. Make it so if total count is explicitly given and it is
greater than the length of the given array. #516
Merge branch 'master' of https://github.com/amatsuda/kaminari