When the repository has multiple arches, eg. i686 and x86_64, it should
add a new entry to the project's builds list, not create a new project
in the list.
This handles that by adding a modified insort_left function and
examining the packages returned from dnf to make sure they aren't
already listed in the results. It also handles adding them in sorted
order so that no further sorting needs to be done on the results.
Resolves: rhbz#1657055
(cherry picked from commit 663a0dcd73)
