[context] Create new repo instead of reusing old one (RhBug:1795004)
[context] Create new repo instead of reusing old one (RhBug:1795004)

Function dnf_repo_check_internal() was reusing a libdnf::Repo objects.
They were detached from libsolv repository and reseted for new usage.

New libdnf::Repo class instantions are created now. The old remain
connected with libsolv repository.
It solve  some PackageKit problems.
eg. https://bugzilla.redhat.com/show_bug.cgi?id=1795004

Closes: #887
Approved by: lukash

rpm-software-management/libdnf,hughsie/libhif,hughsie/libhif,hughsie/libhif,rpm-software-management/libdnf,hughsie/libhif,rpm-software-management/libhif,rpm-software-management/libhif,rpm-software-management/libdnf,rpm-software-management/libhif,rpm-software-management/libdnf,rpm-software-management/libhif