Remi answered me:
> Yes it is - php-pecl-zip is conflicting with php-common in other repos.
No, this is php-common from other repo which stupidly "obsoletes" php-pecl-zip without version limit.
Bad packaging practice. This bug is fixed in fedora / remi repository for a long time.
I really can't take care of all existing third party repository.
> Why not integrate it again inside php-common ?
To make maintenance easier and in sync with system libzip.
php 5.5 have ext zip version 1.11 (libzip 0.10), while pecl/zip is version 1.12 (as in php 5.6, libzip 0.11)