This commit completly drops support for Yum as a depsolving/repoclosure backend. Signed-off-by: Lubomír Sedlář <lsedlar@redhat.com> (cherry picked from commit f5702e4c9d0d5d9d31421d3d47200581e41f02bf)
JIRA: RHELCMP-9800 Signed-off-by: Haibo Lin <hlin@redhat.com>